Chrysler DURANGO 1998 Service MANUAL – Heating and Air Conditioning

DN HEATING AND AIR CONDITIONING 24 - 1

HEATING AND AIR CONDITIONING

CONTENTS

page page

GENERAL INFORMATION

HEATER AND AIR CONDITIONER ............ 2

HEATER AND AIR CONDITIONER CONTROL .. . 3

REAR OVERHEAD AIR CONDITIONER ........ 2

SERVICE WARNINGS AND PRECAUTIONS .... 3

DESCRIPTION AND OPERATION

BLOWER MOTOR ........................ 5

BLOWER MOTOR RELAY .................. 5

BLOWER MOTOR RESISTOR ............... 6

BLOWER MOTOR SWITCH ................. 6

COMPRESSOR .......................... 6

COMPRESSOR CLUTCH ................... 7

COMPRESSOR CLUTCH RELAY ............. 7

CONDENSER ............................ 7

ELECTRONIC CYCLING CLUTCH SWITCH ..... 7

EVAPORATOR COIL ...................... 8

EXPANSION VALVE ....................... 8

FILTER-DRIER ........................... 9

HEATER CORE .......................... 9

HIGH PRESSURE CUT-OFF SWITCH ......... 9

HIGH PRESSURE RELIEF VALVE ............ 9

HIGH SPEED BLOWER MOTOR RELAY ....... 9

LOW PRESSURE CUT-OFF SWITCH ......... 10

REFRIGERANT ......................... 10

REFRIGERANT LINE ..................... 10

REFRIGERANT LINE COUPLER ............ 10

REFRIGERANT OIL ...................... 11

REFRIGERANT SYSTEM SERVICE

EQUIPMENT .......................... 11

REFRIGERANT SYSTEM SERVICE PORT ..... 12

VACUUM CHECK VALVE .................. 12

VACUUM RESERVOIR ................... 12

DIAGNOSIS AND TESTING

A/C PERFORMANCE ..................... 12

BLOWER MOTOR ....................... 19

BLOWER MOTOR RELAY ................. 21

BLOWER MOTOR RESISTOR .............. 21

BLOWER MOTOR SWITCH ................ 22

COMPRESSOR ......................... 22

COMPRESSOR CLUTCH COIL ............. 23

COMPRESSOR CLUTCH RELAY ............ 23

ELECTRONIC CYCLING CLUTCH SWITCH

(Front Unit Only) ...................... 24

EXPANSION VALVE ...................... 24

HEATER PERFORMANCE ................. 16

HEATER-A/C CONTROL .................. 17

HIGH PRESSURE CUT-OFF SWITCH ........ 25

HIGH SPEED BLOWER MOTOR RELAY ...... 25

LOW PRESSURE CUT-OFF SWITCH ......... 26

REFRIGERANT SYSTEM LEAKS ............ 27

VACUUM SYSTEM ...................... 18

SERVICE PROCEDURES

REFRIGERANT OIL LEVEL ................ 28

REFRIGERANT RECOVERY ................ 27

REFRIGERANT SYSTEM CHARGE .......... 28

REFRIGERANT SYSTEM EVACUATE ......... 27

REMOVAL AND INSTALLATION

B-PILLAR REFRIGERANT LINE ............ 43

BLOWER MOTOR ....................... 57

BLOWER MOTOR RELAY ................. 47

BLOWER MOTOR RESISTOR .............. 48

COMPRESSOR ......................... 31

COMPRESSOR CLUTCH .................. 32

COMPRESSOR CLUTCH RELAY ............ 35

CONDENSER ........................... 40

DUCTS AND OUTLETS ................... 63

ELECTRONIC CYCLING CLUTCH SWITCH .... 36

EVAPORATOR COIL ..................... 61

EXPANSION VALVE ...................... 38

FILTER-DRIER .......................... 40

HEATER CORE ......................... 60

HEATER-A/C CONTROL .................. 46

HEATER-A/C HOUSING ................... 52

HEATER-A/C HOUSING DOOR ............. 59

HIGH PRESSURE CUT-OFF SWITCH ........ 29

HIGH SPEED BLOWER MOTOR RELAY ...... 47

LIQUID LINE ........................... 36

LOW PRESSURE CUT-OFF SWITCH ......... 35

MODE DOOR VACUUM ACTUATOR ......... 51

REAR BLOWER MOTOR SWITCH .......... 47

REAR OVERHEAD A/C UNIT ............... 56

REFRIGERANT LINE COUPLER ............ 29

SUCTION AND DISCHARGE LINE .......... 30

SUCTION LINE JUMPER ................. 38

TEMPERATURE CONTROL CABLE .......... 50

UNDERBODY REFRIGERANT LINE .......... 41

24 - 2 HEATING AND AIR CONDITIONING DN

VACUUM CHECK VALVE .................. 44

VACUUM RESERVOIR ................... 45

GENERAL INFORMATION

HEATER AND AIR CONDITIONER

All vehicles are equipped with a common heater­A/C housing assembly (Fig. 1). The system combines
air conditioning, heating, and ventilating capabilities
in a single unit housing mounted under the instru­ment panel.

Fig. 1 Common Blend-Air Heater-Air Conditioner

System - Typical

Outside fresh air enters the vehicle through the
cowl top opening at the base of the windshield, and
passes through a plenum chamber to the heater-A/C

system blower housing. Air flow velocity can then be
adjusted with the blower motor speed selector switch
on the heater-A/C control panel. The air intake open­ings must be kept free of snow, ice, leaves, and other
obstructions for the heater-A/C system to receive a
sufficient volume of outside air.

It is also important to keep the air intake openings
clear of debris because leaf particles and other debris
that is small enough to pass through the cowl ple­num screen can accumulate within the heater-A/C
housing. The closed, warm, damp and dark environ­ment created within the heater-A/C housing is ideal
for the growth of certain molds, mildews and other
fungi. Any accumulation of decaying plant matter
provides an additional food source for fungal spores,
which enter the housing with the fresh air. Excess
debris, as well as objectionable odors created by
decaying plant matter and growing fungi can be dis­charged into the passenger compartment during
heater-A/C system operation.

The heater and air conditioner are blend-air type
systems. In a blend-air system, a blend-air door con­trols the amount of unconditioned air or cooled air

ADJUSTMENTS

TEMPERATURE CONTROL CABLE .......... 67

from the evaporator that is allowed to flow through,
or around, the heater core. A temperature control
knob on the heater-A/C control panel determines the
discharge air temperature by moving a cable, which
operates the blend-air door. This allows an almost
immediate manual control of the output air tempera­ture of the system.

The mode control knob on the heater-A/C control
panel is used to direct the conditioned air to the
selected system outlets. The mode control switch uses
engine vacuum to control the mode doors, which are
operated by vacuum actuator motors.

The outside air intake can be shut off by selecting
the recirculation mode (Max A/C) with the mode con­trol knob. This will operate a vacuum actuated recir­culating air door that closes off the outside fresh air
intake and recirculates the air that is already inside
the vehicle.

A large central duct delivers conditioned air from
the front heater-A/C housing to the second and third
seat floor panel foot wells. A damper door in this duct
can be adjusted by the second seat passengers with a
manual control located on a mini-console just behind
the split bench seat center cushion, or located on the
upper rear surface of the floor console on models with
the optional bucket seats. The split bench seat con­trol has two positions: On or Off. The bucket seat
control has three positions: On, Off and a third posi­tion that directs air flow through a pair of adjustable
barrel outlets mounted high on the rear surface of
the floor console.

The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con­ditioning system has an evaporator to cool and dehu­midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a ther­mal expansion valve between the condenser and the
evaporator coil to meter refrigerant flow to the evap­orator coil. To maintain minimum evaporator temper­ature and prevent evaporator freezing, an electronic
cycling clutch switch on the expansion valve cycles
the compressor clutch.

REAR OVERHEAD AIR CONDITIONER

A rear overhead air conditioning unit is an avail­able option to supplement the output of the front air
conditioner, for increased rear seat passenger com­fort. This unit includes a roof-mounted evaporator
coil and a blower motor with a wide squirrel-cage
type blower wheel. A four position (three speeds plus
off) rear blower motor switch is mounted in the head­liner behind the right front seat position, where it is
accessible to both the driver and the second seat pas­sengers.

DN HEATING AND AIR CONDITIONING 24 - 3

GENERAL INFORMATION (Continued)

The wide and shallow rear unit is positioned
between the front and second seats to provide ample
headroom for all vehicle occupants. The headliner is
molded to cover the unit and includes an integral air
intake grille toward the front of the unit, and an
opening for a snap-in outlet bezel that includes four
adjustable outlet barrels toward the rear of the unit.
A condensate tray is integral to the lower unit hous­ing, and water is drained out of the unit through
hoses located behind the trim on each of the B-pil­lars.

The rear overhead air conditioner will provide cool­ing only when an air conditioning mode is selected
with the front heater and A/C controls, but the rear
blower will operate independent of the front controls
to circulate the interior air if desired.

HEATER AND AIR CONDITIONER CONTROL

Both the heater and A/C systems use a combina­tion of mechanical, electrical, and vacuum controls.
These controls provide the vehicle operator with a
number of setting options to help control the climate
and comfort within the vehicle. Refer to the owner’s
manual in the vehicle glove box for more information
on the features, use, and suggested operation of these
controls.

The heater-A/C control panel is located to the right
of the instrument cluster on the instrument panel.
The control panel contains a rotary-type temperature
control knob, a rotary-type mode control switch knob,
and a rotary-type blower motor speed switch knob.

The heater-A/C control panel cannot be repaired. If
faulty or damaged, the entire unit must be replaced.

The illumination lamps are available for service
replacement.

SERVICE WARNINGS AND PRECAUTIONS

WARNING:

• THE AIR CONDITIONING SYSTEM CONTAINS

REFRIGERANT UNDER HIGH PRESSURE. SEVERE

PERSONAL INJURY MAY RESULT FROM IMPROPER
SERVICE PROCEDURES. REPAIRS SHOULD ONLY
BE PERFORMED BY QUALIFIED SERVICE PERSON­NEL.

• AVOID BREATHING THE REFRIGERANT AND
REFRIGERANT OIL VAPOR OR MIST. EXPOSURE
MAY IRRITATE THE EYES, NOSE, AND/OR THROAT.
WEAR EYE PROTECTION WHEN SERVICING THE
AIR CONDITIONING REFRIGERANT SYSTEM. SERI­OUS EYE INJURY CAN RESULT FROM DIRECT
CONTACT WITH THE REFRIGERANT. IF EYE CON­TACT OCCURS, SEEK MEDICAL ATTENTION IMME­DIATELY.

• DO NOT EXPOSE THE REFRIGERANT TO
OPEN FLAME. POISONOUS GAS IS CREATED
WHEN REFRIGERANT IS BURNED. AN ELEC­TRONIC LEAK DETECTOR IS RECOMMENDED.

• IF ACCIDENTAL SYSTEM DISCHARGE
OCCURS, VENTILATE THE WORK AREA BEFORE
RESUMING SERVICE. LARGE AMOUNTS OF
REFRIGERANT RELEASED IN A CLOSED WORK
AREA WILL DISPLACE THE OXYGEN AND CAUSE
SUFFOCATION.

• THE EVAPORATION RATE OF R-134a REFRIG­ERANT AT AVERAGE TEMPERATURE AND ALTI­TUDE IS EXTREMELY HIGH. AS A RESULT,
ANYTHING THAT COMES IN CONTACT WITH THE
REFRIGERANT WILL FREEZE. ALWAYS PROTECT
THE SKIN OR DELICATE OBJECTS FROM DIRECT
CONTACT WITH THE REFRIGERANT.

• THE R-134a SERVICE EQUIPMENT OR THE
VEHICLE REFRIGERANT SYSTEM SHOULD NOT BE
PRESSURE TESTED OR LEAK TESTED WITH COM­PRESSED AIR. SOME MIXTURES OF AIR AND
R-134a HAVE BEEN SHOWN TO BE COMBUSTIBLE
AT ELEVATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS, AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP­ERTY DAMAGE.

24 - 4 HEATING AND AIR CONDITIONING DN

GENERAL INFORMATION (Continued)

CAUTION:

• Liquid refrigerant is corrosive to metal sur­faces. Follow the operating instructions supplied
with the service equipment being used.

• Never add R-12 to a refrigerant system
designed to use R-134a. Damage to the system will
result.

• R-12 refrigerant oil must not be mixed with
R-134a refrigerant oil. They are not compatible.

• Do not use R-12 equipment or parts on the
R-134a system. Damage to the system will result.

• Do not overcharge the refrigerant system. This
will cause excessive compressor head pressure
and can cause noise and system failure.

• Recover the refrigerant before opening any fit­ting or connection. Open the fittings with caution,
even after the system has been discharged. Never
open or loosen a connection before recovering the
refrigerant.

• Do not remove the secondary retention clip
from any spring-lock coupler connection while the
refrigerant system is under pressure. Recover the
refrigerant before removing the secondary retention
clip. Open the fittings with caution, even after the
system has been discharged. Never open or loosen
a connection before recovering the refrigerant.

• The refrigerant system must always be evacu­ated before charging.

• Do not open the refrigerant system or uncap a
replacement component until you are ready to ser­vice the system. This will prevent contamination in
the system.

• Before disconnecting a component, clean the

outside of the fittings thoroughly to prevent con­tamination from entering the refrigerant system.

• Immediately after disconnecting a component
from the refrigerant system, seal the open fittings
with a cap or plug.

• Before connecting an open refrigerant fitting,
always install a new seal or gasket. Coat the fitting
and seal with clean refrigerant oil before connect­ing.

• Do not remove the sealing caps from a replace­ment component until it is to be installed.

• When installing a refrigerant line, avoid sharp
bends that may restrict refrigerant flow. Position the
refrigerant lines away from exhaust system compo­nents or any sharp edges, which may damage the
line.

• Tighten refrigerant fittings only to the specified
torque. The aluminum fittings used in the refriger­ant system will not tolerate overtightening.

• When disconnecting a refrigerant fitting, use a
wrench on both halves of the fitting. This will pre­vent twisting of the refrigerant lines or tubes.

• Refrigerant oil will absorb moisture from the
atmosphere if left uncapped. Do not open a con­tainer of refrigerant oil until you are ready to use it.
Replace the cap on the oil container immediately
after using. Store refrigerant oil only in a clean, air­tight, and moisture-free container.

• Keep service tools and the work area clean.
Contamination of the refrigerant system through
careless work habits must be avoided.

COOLING SYSTEM REQUIREMENTS

To maintain the performance level of the heating­air conditioning system, the engine cooling system
must be properly maintained. The use of a bug
screen is not recommended. Any obstructions in front
of the radiator or condenser will reduce the perfor­mance of the air conditioning and engine cooling sys­tems.

The engine cooling system includes the heater core
and the heater hoses. Refer to Group 7 - Cooling Sys­tem for more information before the opening of, or
attempting any service to the engine cooling system.

REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS

Kinks or sharp bends in the refrigerant plumbing
will reduce the capacity of the entire system. High
pressures are produced in the system when it is oper­ating. Extreme care must be exercised to make sure
that all refrigerant system connections are pressure
tight.

A good rule for the flexible hose refrigerant lines is
to keep the radius of all bends at least ten times the
diameter of the hose. Sharp bends will reduce the
flow of refrigerant. The flexible hose lines should be
routed so they are at least 80 millimeters (3 inches)
from the exhaust manifold. It is a good practice to
inspect all flexible refrigerant system hose lines at
least once a year to make sure they are in good con­dition and properly routed.

There are two types of refrigerant fittings:

• All fittings with O-rings need to be coated with
refrigerant oil before installation. Use only O-rings
that are the correct size and approved for use with
R-134a refrigerant. Failure to do so may result in a
leak.

• Unified plumbing connections with gaskets can­not be serviced with O-rings. The gaskets are not
reusable and new gaskets do not require lubrication
before installing.

Using the proper tools when making a refrigerant
plumbing connection is very important. Improper
tools or improper use of the tools can damage the
refrigerant fittings. Always use two wrenches when
loosening or tightening tube fittings. Use one wrench
to hold one side of the connection stationary, while

DN HEATING AND AIR CONDITIONING 24 - 5

GENERAL INFORMATION (Continued)

loosening or tightening the other side of the connec­tion with a second wrench.

The refrigerant must be recovered completely from
the system before opening any fitting or connection.
Open the fittings with caution, even after the refrig­erant has been recovered. If any pressure is noticed
as a fitting is loosened, tighten the fitting and
recover the refrigerant from the system again.

Do not discharge refrigerant into the atmosphere.
Use an R-134a refrigerant recovery/recycling device
that meets SAE Standard J2210.

The refrigerant system will remain chemically sta­ble as long as pure, moisture-free R-134a refrigerant
and refrigerant oil is used. Dirt, moisture, or air can
upset this chemical stability. Operational troubles or
serious damage can occur if foreign material is
present in the refrigerant system.

When it is necessary to open the refrigerant sys­tem, have everything needed to service the system
ready. The refrigerant system should not be left open
to the atmosphere any longer than necessary. Cap or
plug all lines and fittings as soon as they are opened
to prevent the entrance of dirt and moisture. All lines
and components in parts stock should be capped or
sealed until they are to be installed.

All tools, including the refrigerant recycling equip­ment, the manifold gauge set, and test hoses should
be kept clean and dry. All tools and equipment must
be designed for R-134a refrigerant.

switch, the blower motor resistor, and the high speed
blower motor relay.

The blower motor and blower motor wheel cannot
be repaired and, if faulty or damaged, they must be
replaced. The blower motor and blower wheel are
each serviced separately.

REAR

The rear blower motor and blower wheel are
mounted to a blower wheel housing located inside the
rear overhead A/C unit, above the headliner. The
blower motor controls the velocity of air flowing
through the overhead A/C unit by spinning a wide
squirrel cage-type blower wheel within the housing
at the selected speed. Rear blower motor speed is
controlled by regulating the ground path through the
rear blower motor switch and the rear blower motor
resistor.

The rear blower motor will only operate when the
ignition switch is in the On position. The rear blower
motor receives a fused battery feed through a fuse in
the relay and fuse block whenever the ignition switch
is in the On position. The relay and fuse block is
attached to the back of the junction block, under the
left side of the instrument panel in the passenger
compartment.

The rear blower motor, blower wheel, and blower
wheel housing cannot be repaired and, if faulty or
damaged, they must be replaced as a complete facto­ry-balanced unit.

DESCRIPTION AND OPERATION

BLOWER MOTOR

FRONT

The blower motor and blower wheel are located in
the passenger side end of the heater-A/C housing,
below the glove box. The blower motor controls the
velocity of air flowing through the heater-A/C hous­ing by spinning a squirrel cage-type blower wheel
within the housing at the selected speed. The blower
motor and blower wheel can only be serviced with
the heater-A/C housing removed from the passenger
compartment.

The blower motor will only operate when the igni­tion switch is in the On position, and the heater-A/C
mode control switch knob is in any position, except
Off. The blower motor receives a fused battery feed
through the blower motor relay whenever the igni­tion switch is in the On position.

The blower motor battery feed circuit is protected
by a fuse in the Power Distribution Center (PDC).
The blower motor relay control circuit is protected by
a fuse in the junction block. Blower motor speed is
controlled by regulating the ground path through the
heater-A/C mode control switch, the blower motor

BLOWER MOTOR RELAY

The blower motor relay is a International Stan­dards Organization (ISO)-type relay. The relay is a
electromechanical device that switches battery cur­rent from a fuse in the Power Distribution Center
(PDC) directly to the blower motor. The relay is ener­gized when the relay coil is provided a voltage signal
by the ignition switch. This arrangement reduces the
amount of battery current that must flow through
the ignition switch.

The blower motor relay control circuit is protected
by a fuse located in the junction block. When the
relay is de-energized, the blower motor receives no
battery current. See Blower Motor Relay in the Diag­nosis and Testing section of this group for more infor­mation.

The blower motor relay is located in the PDC in
the engine compartment. Refer to the PDC label for
blower motor relay identification and location.

The blower motor relay cannot be repaired and, if
faulty or damaged, it must be replaced.

24 - 6 HEATING AND AIR CONDITIONING DN

DESCRIPTION AND OPERATION (Continued)

BLOWER MOTOR RESISTOR

FRONT

During vehicle assembly, the blower motor resistor
is mounted to the dash plenum panel inside the pas­senger compartment prior to instrument panel
roll-up (Fig. 2). However, a resistor mounting plate
has been designed so that the resistor can be
removed through an access hole in the cowl plenum
panel just below the windshield. It can be accessed
by removing the cowl plenum cover/grille panel. See
Blower Motor Resistor in the Removal and Installa­tion section of this group for more information.

Fig. 2 Blower Motor Resistor - Factory Installation

The resistor has multiple resistor wires, each of
which will change the resistance in the blower motor
ground path to change the blower motor speed. The
blower motor switch directs the ground path through
the correct resistor wire to obtain the selected blower
motor speed.

With the blower motor switch in the lowest speed
position, the ground path for the motor is applied
through all of the resistor wires. Each higher speed
selected with the blower motor switch applies the
blower motor ground path through fewer of the resis­tor wires, increasing the blower motor speed. When
the blower motor switch is in the highest speed posi­tion, the blower motor resistor is bypassed and the
blower motor receives a direct path to ground
through the high speed blower motor relay.

The blower motor resistor cannot be repaired and,
if faulty or damaged, it must be replaced.

REAR

The blower motor resistor for the optional rear
overhead A/C unit is located within the unit housing.
The resistor has multiple resistor wires, each of

which will change the resistance in the blower motor
ground path to change the blower motor speed. The
blower motor switch directs the ground path through
the correct resistor wire to obtain the selected blower
motor speed.

With the blower motor switch in the lowest speed
position, the ground path for the motor is applied
through all of the resistor wires. Each higher speed
selected with the blower motor switch applies the
blower motor ground path through fewer of the resis­tor wires, increasing the blower motor speed. When
the blower motor switch is in the highest speed posi­tion, the blower motor resistor is bypassed and the
blower motor receives a direct path to ground.

The blower motor resistor cannot be repaired and,
if faulty or damaged, it must be replaced.

BLOWER MOTOR SWITCH

FRONT

The heater-A/C blower motor is controlled by a four
position rotary-type blower motor switch, mounted in
the heater-A/C control panel. The switch allows the
selection of one of four blower motor speeds, but can
only be turned off by selecting the Off position with
the heater-A/C mode control switch knob.

The blower motor switch directs the blower motor
ground path through the mode control switch to the
blower motor resistor, or directly to ground through
the high speed blower motor relay, as required to
achieve the selected blower motor speed.

The blower motor switch cannot be repaired and, if
faulty or damaged, the entire heater-A/C control unit
must be replaced. The blower motor switch knob is
serviced separately.

REAR

The optional rear overhead A/C unit blower motor
is controlled by a four position rotary-type blower
motor switch, mounted by a snap fit in a hole in the
headliner over the right front seat back. The switch
allows the selection of one of three blower motor
speeds and an Off position. The blower motor switch
directs the blower motor ground path through the
blower motor resistor.

The blower motor switch cannot be repaired and, if
faulty or damaged, the entire switch unit must be
replaced. The blower motor switch has a replaceable
incandescent-type illumination lamp bulb.

COMPRESSOR

The air conditioning system uses a Sanden
SD7H15 seven cylinder, reciprocating wobble plate­type compressor on all models. This compressor has a
fixed displacement of 150 cubic centimeters (9.375
cubic inches), and has both the suction and discharge
ports located on the cylinder head. A label identifying

DN HEATING AND AIR CONDITIONING 24 - 7

DESCRIPTION AND OPERATION (Continued)

the use of R-134a refrigerant is located on the com­pressor.

The compressor is driven by the engine through an
electric clutch, drive pulley and belt arrangement.
The compressor is lubricated by refrigerant oil that is
circulated throughout the refrigerant system with the
refrigerant.

The compressor draws in low-pressure refrigerant
vapor from the evaporator through its suction port. It
then compresses the refrigerant into a high-pressure,
high-temperature refrigerant vapor, which is then
pumped to the condenser through the compressor dis­charge port.

The compressor cannot be repaired. If faulty or
damaged, the entire compressor assembly must be
replaced. The compressor clutch, pulley and clutch
coil are available for service.

COMPRESSOR CLUTCH

The compressor clutch assembly consists of a sta­tionary electromagnetic coil, a hub bearing and pul­ley assembly, and a clutch plate (Fig. 3). The
electromagnetic coil unit and the hub bearing and
pulley assembly are each retained on the nose of the
compressor front housing with snap rings. The clutch
plate is mounted to the compressor shaft and secured
with a nut.

switch, the compressor clutch relay, and the Power­train Control Module (PCM). The PCM may delay
compressor clutch engagement for up to thirty sec­onds. Refer to Group 14 - Fuel System for more infor­mation on the PCM controls.

COMPRESSOR CLUTCH RELAY

The compressor clutch relay is a International
Standards Organization (ISO) micro-relay. The termi­nal designations and functions are the same as a con­ventional ISO relay. However, the micro-relay
terminal orientation (footprint) is different, the cur­rent capacity is lower, and the relay case dimensions
are smaller than those of the conventional ISO relay.

The compressor clutch relay is a electromechanical
device that switches battery current to the compres­sor clutch coil when the Powertrain Control Module
(PCM) grounds the coil side of the relay. The PCM
responds to inputs from the heater-A/C mode control
switch, the electronic cycling clutch switch, the low
pressure cut-off switch, and the high pressure cut-off
switch. See Compressor Clutch Relay in the Diagno­sis and Testing section of this group for more infor­mation.

The compressor clutch relay is located in the Power
Distribution Center (PDC) in the engine compart­ment. Refer to the PDC label for relay identification
and location.

The compressor clutch relay cannot be repaired
and, if faulty or damaged, it must be replaced.

Fig. 3 Compressor Clutch - Typical

These components provide the means to engage
and disengage the compressor from the engine ser­pentine accessory drive belt. When the clutch coil is
energized, it magnetically draws the clutch into con­tact with the pulley and drives the compressor shaft.
When the coil is not energized, the pulley freewheels
on the clutch hub bearing, which is part of the pulley.
The compressor clutch and coil are the only serviced
parts on the compressor.

The compressor clutch engagement is controlled by
several components: the heater-A/C mode control
switch, the electronic cycling clutch switch, the low
pressure cut-off switch, the high pressure cut-off

CONDENSER

The condenser is located in the air flow in front of
the engine cooling radiator. The condenser is a heat
exchanger that allows the high-pressure refrigerant
gas being discharged by the compressor to give up its
heat to the air passing over the condenser fins. When
the refrigerant gas gives up its heat, it condenses.
When the refrigerant leaves the condenser, it has
become a high-pressure liquid refrigerant.

The volume of air flowing over the condenser fins
is critical to the proper cooling performance of the air
conditioning system. Therefore, it is important that
there are no objects placed in front of the radiator
grille openings in the front of the vehicle or foreign
material on the condenser fins that might obstruct
proper air flow. Also, any factory-installed air seals or
shrouds must be properly reinstalled following radia­tor or condenser service.

The condenser cannot be repaired and, if faulty or
damaged, it must be replaced.

ELECTRONIC CYCLING CLUTCH SWITCH

The Electronic Cycling Clutch Switch (ECCS) is
mounted to the outboard side of the thermal expan­sion valve in the engine compartment. A thermistor

24 - 8 HEATING AND AIR CONDITIONING DN

DESCRIPTION AND OPERATION (Continued)

probe within a capillary tube on the switch is
inserted into a well on the side of the expansion
valve filled with a thermally-conductive grease. This
arrangement allows the ECCS to monitor the tem­perature of the expanded refrigerant entering the
evaporator.

The function of the ECCS is to prevent refrigerant
temperatures from becoming so low that condensa­tion freezes on the evaporator fins. This condition is
referred to as evaporator icing. Evaporator icing
reduces air conditioning system air flow and cooling
performance.

The ECCS is connected in series electrically with
the heater-A/C mode control switch, the low pressure
cut-off switch and the high pressure cut-off switch
between ground and the Powertrain Control Module
(PCM). The ECCS will open when it monitors a
refrigerant temperature below about 2.9° C (37.2° F),
and will close again when the refrigerant tempera­ture reaches about 4.3° C (39.7° F). The opening and
closing of the ECCS signals the PCM to cycle the
compressor clutch on and off through the compressor
clutch relay.

The ECCS is a factory sealed and calibrated unit
and cannot be adjusted or repaired. If faulty or dam­aged, the ECCS must be replaced.

EVAPORATOR COIL

FRONT

The evaporator coil is located in the heater-A/C
housing, under the instrument panel. The evaporator
coil is positioned in the heater-A/C housing so that

all air that enters the housing must pass over the
fins of the evaporator before it is distributed through
the system ducts and outlets. However, air passing
over the evaporator coil fins will only be conditioned
when the compressor is engaged and circulating
refrigerant through the evaporator coil tubes.

Refrigerant enters the evaporator from the expan­sion valve as a low-temperature, low-pressure mix­ture of liquid and gas. As air flows over the fins of
the evaporator, the humidity in the air condenses on
the fins, and the heat from the air is absorbed by the
refrigerant. Heat absorption causes the refrigerant to
boil and vaporize. The refrigerant becomes a high­temperature, low-pressure gas before it leaves the
evaporator.

The evaporator coil cannot be repaired and, if
faulty or damaged, it must be replaced.

REAR

The rear evaporator coil is located in the rear over­head A/C unit housing, above the headliner. The
evaporator coil is positioned in the overhead A/C unit
housing so that all air that enters the housing must
pass over the fins of the evaporator before it is dis-

tributed through the system outlets. However, air
passing over the evaporator coil fins will only be con­ditioned when the compressor is engaged and circu­lating refrigerant through the evaporator coil tubes.

Refrigerant enters the evaporator from the rear
expansion valve as a low-temperature, low-pressure
mixture of liquid and gas. As air flows over the fins
of the evaporator, the humidity in the air condenses
on the fins, and the heat from the air is absorbed by
the refrigerant. Heat absorption causes the refriger­ant to boil and vaporize. The refrigerant becomes a
high-temperature, low-pressure gas before it leaves
the evaporator.

The rear evaporator coil cannot be repaired and, if
faulty or damaged, the rear evaporator coil must be
replaced.

EXPANSION VALVE

FRONT

The front “H” valve-type thermal expansion valve
(TXV) is located at the dash panel between the liquid
and suction lines, and the evaporator coil. High-pres­sure, high temperature liquid refrigerant from the
liquid line passes through the expansion valve ori­fice, converting it into a low-pressure, low-tempera­ture mixture of liquid and gas before it enters the
evaporator coil.

A temperature sensor in the expansion valve con­trol head monitors the temperature of the refrigerant
leaving the evaporator coil through the suction line,
and adjusts the orifice size at the liquid line to let
the proper amount of refrigerant into the evaporator
coil to meet the vehicle cooling requirements. Con­trolling the refrigerant flow through the evaporator
ensures that none of the refrigerant leaving the evap­orator is still in a liquid state, which could damage
the compressor.

The expansion valve is a factory calibrated unit
and cannot be adjusted or repaired. If faulty or dam­aged, the expansion valve must be replaced.

REAR

Vehicles equipped with the optional rear overhead
A/C unit have an H-type thermal expansion valve
(TXV) located underneath the passenger side of the
vehicle floor panel, next to the sill. It performs the
same function as the front expansion valve, to moni­tor refrigerant temperature at the control head and
meter the refrigerant entering the evaporator to meet
the vehicle cooling requirements.

The rear expansion valve is a factory calibrated
unit and cannot be adjusted or repaired. If faulty or
damaged, the rear expansion valve unit must be
replaced.

DN HEATING AND AIR CONDITIONING 24 - 9

DESCRIPTION AND OPERATION (Continued)

FILTER-DRIER

The filter-drier is mounted on the right front
wheelhouse front extension in the engine compart­ment, in the liquid line between the condenser outlet
and the evaporator inlet. Refrigerant enters the fil­ter-drier as a high-pressure, high-temperature liquid.

The filter-drier performs a filtering action to pre­vent foreign material in the refrigerant from contam­inating the expansion valve. A desiccant bag is
mounted inside the filter-drier canister to absorb any
moisture which may have entered and become
trapped within the refrigerant system. In addition,
during periods of high demand air conditioner opera­tion, the filter-drier acts as a reservoir to store sur­plus refrigerant.

The filter-drier cannot be repaired. If the filter­drier is faulty or damaged, or if the refrigerant sys­tem has been contaminated or left open to the
atmosphere for an indeterminable period, it must be
replaced.

HEATER CORE

The heater core is located in the heater-A/C hous­ing, under the instrument panel. It is a heat
exchanger made of rows of tubes and fins. Engine
coolant is circulated through heater hoses to the
heater core at all times. As the coolant flows through
the heater core, heat removed from the engine is
transferred to the heater core fins and tubes.

Air directed through the heater core picks up the
heat from the heater core fins. The blend air door
allows control of the heater output air temperature

by controlling how much of the air flowing through
the heater-A/C housing is directed through the
heater core. The blower motor speed controls the vol­ume of air flowing through the heater-A/C housing.

The heater core cannot be repaired and, if faulty or
damaged, it must be replaced. Refer to Group 7 ­Cooling System for more information on the engine
cooling system, the engine coolant and the heater
hoses.

HIGH PRESSURE CUT-OFF SWITCH

The high pressure cut-off switch is located on the
discharge line near the compressor. The switch is
screwed onto a fitting that contains a Schrader-type
valve, which allows the switch to be serviced without
discharging the refrigerant system. The discharge
line fitting is equipped with an O-ring to seal the
switch connection.

The high pressure cut-off switch is connected in
series electrically with the electronic cycling clutch
switch and the low pressure cut-off switch between
ground and the Powertrain Control Module (PCM).
The switch contacts open and close causing the PCM
to turn the compressor clutch on and off. This pre-

vents compressor operation when the discharge line
pressure approaches high levels.

The high pressure cut-off switch contacts are open
when the discharge line pressure rises above about
3100 to 3375 kPa (450 to 490 psi). The switch con­tacts will close when the discharge line pressure
drops to about 1860 to 2275 kPa (270 to 330 psi).

The high pressure cut-off switch is a factory-cali­brated unit. The switch cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.

HIGH PRESSURE RELIEF VALVE

A high pressure relief valve is located on the com­pressor cylinder head, which is at the rear of the
compressor. This mechanical valve is designed to
vent refrigerant from the system to protect against
damage to the compressor and other system compo­nents, caused by condenser air flow restriction or an
overcharge of refrigerant.

The high pressure relief valve vents the system
when a discharge pressure of 3445 to 4135 kPa (500
to 600 psi) or above is reached. The valve closes with
a minimum discharge pressure of 2756 kPa (400 psi)
is reached.

The high pressure relief valve vents only enough
refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con­served in the system. If the valve vents refrigerant, it
does not mean the valve is faulty.

The high pressure relief valve is a factory-cali­brated unit. The valve cannot be adjusted or
repaired, and must not be removed or otherwise dis­turbed. The valve is only serviced as a part of the
compressor assembly.

HIGH SPEED BLOWER MOTOR RELAY

The front blower motor electrical circuit uses a
high speed blower motor relay. The high speed
blower motor relay is a International Standards
Organization (ISO)-type relay. The relay is a electro­mechanical device that switches the blower motor to
ground, bypassing the remainder of the blower motor
feed circuit.

The high speed blower motor relay is energized
when the relay coil is provided a ground signal by
the blower motor switch, and a battery feed from the
ignition switch. When the relay is de-energized, the
front blower motor ground feed is routed through the
front blower motor switch and the blower motor
resistor. See High Speed Blower Motor Relay in the
Diagnosis and Testing section of this group for more
information.

The high speed blower motor relay is located in the
relay and fuse block, which is attached to the back of
the junction block, under the left side of the instru-

24 - 10 HEATING AND AIR CONDITIONING DN

DESCRIPTION AND OPERATION (Continued)

ment panel in the passenger compartment. The high
speed blower motor relay cannot be repaired and, if
faulty or damaged, it must be replaced.

LOW PRESSURE CUT-OFF SWITCH

The low pressure cut-off switch is located on the
suction line jumper near the dash panel in the
engine compartment. The switch is screwed onto a
fitting on the suction line jumper that contains a
Schrader-type valve, which allows the switch to be
serviced without discharging the refrigerant system.
The suction line jumper fitting is equipped with an
O-ring to seal the switch connection.

The low pressure cut-off switch is connected in
series electrically with the high pressure cut-off
switch, the electronic cycling clutch switch and the
heater-A/C controls, between ground and the Power­train Control Module (PCM). The switch contacts
open and close causing the PCM to turn the compres­sor clutch on and off. This helps to regulate the
refrigerant system pressure and protects the com­pressor from damage due to loss of refrigerant and
refrigerant oil.

The low pressure cut-off switch contacts are open
when the suction pressure is about 68.9 kPa (10 psi)
or lower. The switch contacts will close when the suc­tion pressure rises to about 89.6 to 186.1 kPa (13 to
27 psi) or above. Lower ambient temperatures, below
about -1° C (30° F), will also cause the switch con­tacts to open. This is due to the pressure/tempera­ture relationship of the refrigerant in the system.

The low pressure cut-off switch is a factory-cali­brated unit. It cannot be adjusted or repaired and, if

faulty or damaged, it must be replaced.

REFRIGERANT

The refrigerant used in this air conditioning sys­tem is a HydroFluoroCarbon (HFC), type R-134a.
Unlike R-12, which is a ChloroFluoroCarbon (CFC),
R-134a refrigerant does not contain ozone-depleting
chlorine. R-134a refrigerant is a non-toxic, non-flam­mable, clear, and colorless liquefied gas.

Even though R-134a does not contain chlorine, it
must be reclaimed and recycled just like CFC-type
refrigerants. This is because R-134a is a greenhouse
gas and can contribute to global warming.

R-134a refrigerant is not compatible with R-12
refrigerant in an air conditioning system. Even a
small amount of R-12 added to an R-134a refrigerant
system will cause compressor failure, refrigerant oil
sludge or poor air conditioning system performance.
In addition, the PolyAlkylene Glycol (PAG) synthetic
refrigerant oils used in an R-134a refrigerant system
are not compatible with the mineral-based refriger­ant oils used in an R-12 refrigerant system.

R-134a refrigerant system service ports, service
tool couplers and refrigerant dispensing bottles have
all been designed with unique fittings to ensure that
an R-134a system is not accidentally contaminated
with the wrong refrigerant (R-12). There are also
labels posted in the engine compartment of the vehi­cle and on the compressor identifying to service tech­nicians that the air conditioning system is equipped
with R-134a.

REFRIGERANT LINE

The refrigerant lines and hoses are used to carry
the refrigerant between the various air conditioning
system components. A barrier hose design with a
nylon tube inner hose liner is used for the R-134a air
conditioning system on this vehicle. This nylon liner
helps to further contain the R-134a refrigerant,
which has a smaller molecular structure than R-12
refrigerant. The ends of the refrigerant hoses are
made from lightweight aluminum, and use braze-less
fittings.

Any kinks or sharp bends in the refrigerant plumb­ing will reduce the capacity of the entire air condi­tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.

High pressures are produced in the refrigerant sys­tem when the air conditioning compressor is operat­ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.

The refrigerant lines and hoses cannot be repaired
and, if faulty or damaged, they must be replaced.

REFRIGERANT LINE COUPLER

Spring-lock type refrigerant line couplers are used
to connect many of the refrigerant lines and other
components to the refrigerant system. These couplers
require a special tool for disengaging the two coupler
halves.

The spring-lock coupler is held together by a garter
spring inside a circular cage on the male half of the
fitting (Fig. 4). When the two coupler halves are con­nected, the flared end of the female fitting slips
behind the garter spring inside the cage on the male
fitting. The garter spring and cage prevent the flared
end of the female fitting from pulling out of the cage.

Two O-rings on the male half of the fitting are
used to seal the connection. These O-rings are com-

DN HEATING AND AIR CONDITIONING 24 - 11

DESCRIPTION AND OPERATION (Continued)

REFRIGERANT SYSTEM SERVICE EQUIPMENT

WARNING: EYE PROTECTION MUST BE WORN
WHEN SERVICING AN AIR CONDITIONING REFRIG­ERANT SYSTEM. TURN OFF (ROTATE CLOCKWISE)
ALL VALVES ON THE EQUIPMENT BEING USED,
BEFORE CONNECTING TO OR DISCONNECTING
FROM THE REFRIGERANT SYSTEM. FAILURE TO
OBSERVE THESE WARNINGS MAY RESULT IN PER­SONAL INJURY.

When servicing the air conditioning system, a
R-134a refrigerant recovery/recycling/charging sta­tion that meets SAE Standard J2210 must be used.
Contact an automotive service equipment supplier for
refrigerant recovery/recycling/charging equipment.

Fig. 4 Spring-Lock Coupler - Typical

patible with R-134a refrigerant and must be replaced
with O-rings made of the same material.

Secondary clips are installed over the two con­nected coupler halves at the factory for added blowoff
protection. In addition, some models have a plastic
ring that is used at the factory as a visual indicator
to confirm that these couplers are connected. After
the coupler is connected, the plastic indicator ring is
no longer needed; however, it will remain on the
refrigerant line near the coupler cage.

Refer to the operating instructions supplied by the
equipment manufacturer for the proper care and use
of this equipment.

A manifold gauge set may be needed with some
recovery/recycling/charging equipment (Fig. 5). The
service hoses on the gauge set being used should
have manual (turn wheel), or automatic back-flow
valves at the service port connector ends. This will
prevent refrigerant from being released into the
atmosphere.

REFRIGERANT OIL

The refrigerant oil used in R-134a refrigerant sys­tems is a synthetic-based, PolyAlkylene Glycol (PAG),
wax-free lubricant. Mineral-based R-12 refrigerant

oils are not compatible with PAG oils, and should
never be introduced to an R-134a refrigerant system.

There are different PAG oils available, and each
contains a different additive package. The SD7H15
compressor used in this vehicle is designed to use an
SP-20 PAG refrigerant oil. Use only refrigerant oil of
this same type to service the refrigerant system.

After performing any refrigerant recovery or recy­cling operation, always replenish the refrigerant sys­tem with the same amount of the recommended
refrigerant oil as was removed. Too little refrigerant
oil can cause compressor damage, and too much can
reduce air conditioning system performance.

PAG refrigerant oil is much more hygroscopic than
mineral oil, and will absorb any moisture it comes
into contact with, even moisture in the air. The PAG
oil container should always be kept tightly capped
until it is ready to be used. After use, recap the oil
container immediately to prevent moisture contami­nation.

Fig. 5 Manifold Gauge Set - Typical

MANIFOLD GAUGE SET CONNECTIONS

CAUTION: Do not use an R-12 manifold gauge set
on an R-134a system. The refrigerants are not com­patible and system damage will result.

24 - 12 HEATING AND AIR CONDITIONING DN

DESCRIPTION AND OPERATION (Continued)

LOW PRESSURE GAUGE HOSE

The low pressure hose (Blue with Black stripe)
attaches to the suction service port. This port is
located on the compressor manifold, directly over the
suction port of the compressor.

HIGH PRESSURE GAUGE HOSE

The high pressure hose (Red with Black stripe)
attaches to the discharge service port. This port is
located on the liquid line between the condenser and
the evaporator, near the front of the engine compart­ment.

RECOVERY/RECYCLING/EVACUATION/CHARGING HOSE

The center manifold hose (Yellow, or White, with
Black stripe) is used to recover, evacuate, and charge
the refrigerant system. When the low or high pres­sure valves on the manifold gauge set are opened,
the refrigerant in the system will escape through this
hose.

REFRIGERANT SYSTEM SERVICE PORT

The two refrigerant system service ports are used
to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system, to
ensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.

The high pressure service port is located on the liq­uid line between the condenser and the evaporator,
near the front of the engine compartment. The low
pressure service port is located on the compressor

manifold, directly over the suction port of the com­pressor.

Each of the service ports has a threaded plastic
protective cap installed over it from the factory. After
servicing the refrigerant system, always reinstall
both of the service port caps.

VACUUM CHECK VALVE

Two vacuum check valves are installed in the
accessory vacuum supply line in the engine compart­ment. One check valve is located near the vacuum
fitting on the power brake booster. The second check
valve is located at the heater and air conditioner
take-out of the accessory vacuum supply line. The
vacuum check valves are designed to allow vacuum
to flow in only one direction through the accessory
vacuum supply circuits.

The use of the vacuum check valves help to main­tain the system vacuum needed to retain the selected
heater-A/C mode settings. The check valves will pre­vent the engine from bleeding down system vacuum
through the intake manifold during extended heavy
engine load (low engine vacuum) operation.

The vacuum check valves cannot be repaired and,
if faulty or damaged, they must be individually
replaced.

VACUUM RESERVOIR

The vacuum reservoir is mounted to the underside
of the cowl plenum cover/grille panel in the right
cowl plenum area. The cowl plenum cover/grille panel
must be removed from the vehicle to access the vac­uum reservoir for service.

Engine vacuum is stored in the vacuum reservoir.
The stored vacuum is used to operate the vacuum­controlled vehicle accessories during periods of low
engine vacuum such as when the vehicle is climbing
a steep grade, or under other high engine load oper­ating conditions.

The vacuum reservoir cannot be repaired and, if
faulty or damaged, it must be replaced.

DIAGNOSIS AND TESTING

A/C PERFORMANCE

The air conditioning system is designed to provide
the passenger compartment with low temperature
and low humidity air. The evaporators, located in the
heater-A/C housing on the dash panel below the
instrument panel and in the rear overhead A/C unit
housing above the headliner, are cooled to tempera­tures near the freezing point. As warm damp air
passes through the cooled evaporators, the air trans­fers its heat to the refrigerant in the evaporator
tubes and the moisture in the air condenses on the
evaporator fins. During periods of high heat and
humidity, an air conditioning system will be more
effective in the recirculation mode (Max-A/C). With
the system in the recirculation mode, only air from
the passenger compartment passes through the evap­orator. As the passenger compartment air dehumidi­fies, the air conditioning system performance levels
improve.

Humidity has an important bearing on the temper­ature of the air delivered to the interior of the vehi­cle. It is important to understand the effect that
humidity has on the performance of the air condition­ing system. When humidity is high, the evaporator
has to perform a double duty. It must lower the air
temperature, and it must lower the temperature of
the moisture in the air that condenses on the evapo­rator fins. Condensing the moisture in the air trans­fers heat energy into the evaporator fins and tubing.
This reduces the amount of heat the evaporator can
absorb from the air. High humidity greatly reduces
the ability of the evaporator to lower the temperature
of the air.

However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Wring-

DN HEATING AND AIR CONDITIONING 24 - 13

DIAGNOSIS AND TESTING (Continued)

ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from their
air conditioning system on humid days. A perfor­mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.

Review the Service Warnings and Precautions in
the General Information section near the front of this
group before performing this procedure. The air tem­perature in the test room and in the vehicle must be
a minimum of 21° C (70° F) for this test.

(1) Connect a tachometer and a manifold gauge
set.

(2) Set the heater-A/C mode control switch knob in
the recirculation mode (Max-A/C) position, the tem­perature control knob in the full cool position, and
the blower motor switch knob in the highest speed
position.

(3) Start the engine and hold the idle at 1,000 rpm
with the compressor clutch engaged. If the compres­sor clutch does not engage, see the A/C Diagnosis
chart in the Diagnosis and Testing section of this
group.

(4) The engine should be at operating temperature.
The doors and windows must be closed and the hood
must be mostly closed.

CAUTION: Never insert a thermometer probe into
the outlet for the optional rear overhead A/C unit.
Failure to observe this caution could result in dam­age to the rear blower wheel and/or the thermome-

ter.

(5) Insert a thermometer in the driver side center
A/C (panel) outlet for testing of the front unit, or
hold a thermometer near the center outlets in the
headliner for testing of the rear unit. Operate the
engine for five minutes.

(6) With the compressor clutch engaged, record the
panel outlet or left center outlet discharge air tem­perature, the condenser out pressure (high side), and
the compressor inlet pressure (low side). The com­pressor clutch may cycle, depending upon the ambi­ent temperature and humidity. If the clutch cycles,
use the readings obtained before the clutch disen­gaged.

(7) Compare the discharge air temperature read­ing to the Performance Temperature and Pressure
chart. If the temperature reading is high for the rear
unit, see Refrigerant System Leaks in the Diagnosis
and Testing section of this group, and Refrigerant
System Charge in the Service Procedures section of
this group. If the temperature reading is high for the
front unit, clamp off both heater hoses (inlet and out­let), wait five minutes and record the temperature
again. Compare the second reading to the Perfor­mance Temperature and Pressure chart. If the tem­perature reading is now OK, see Temperature
Control Cable in the Removal and Installation sec­tion and in the Adjustments section of this group. If
the temperature reading is still too high, see Refrig­erant System Leaks in the Diagnosis and Testing sec­tion of this group, and Refrigerant System Charge in
the Service Procedures section of this group.

Ambient Temperature

Maximum Allowable Air

Temperature at Left Center Panel

Outlet

Compressor Inlet Pressure (Low

Side)

Condenser Out Pressure at

Service Port (High Side)

Performance Temperature and Pressure

21°C

(70°F)

9°C

(48°F)

138 to 207

kPa

(20 to 30 psi)

689 to 1034

kPa

(100 to 150

psi)

27°C

(80°F)

9°C

(48°F)

138 to 207

kPa

(20 to 30 psi)

931 to 1276

kPa

(135 to 185

psi)

32°C

(90°F)

12°C

(54°F)

172 to 241

kPa

(25 to 35 psi)
1172 to 1517

kPa

(170 to 220

psi)

38°C

(100°F)

15°C

(59°F)

214 to 283

kPa

(31 to 41 psi)
1448 to 1758

kPa

(210 to 255

psi)

43°C

(110°F)

18°C

(65°F)

255 to 324

kPa

(37 to 47 psi)
1689 to 2034

kPa

(245 to 295

psi)

24 - 14 HEATING AND AIR CONDITIONING DN

DIAGNOSIS AND TESTING (Continued)

(8) Compare the discharge (high side) and suction
(low side) pressure readings to the Performance Tem­perature and Pressure chart. If the pressures are

CONDITION POSSIBLE CAUSE CORRECTION

RAPID COMPRESSOR
CLUTCH CYCLING (TEN
OR MORE CYCLES PER
MINUTE).

EQUAL PRESSURES,
BUT THE COMPRESSOR
CLUTCH DOES NOT
ENGAGE.

NORMAL PRESSURES,
BUT A/C PERFORMANCE
TEST AIR
TEMPERATURES ARE
TOO HIGH.

1. Low refrigerant system
charge.

2. Faulty electronic cycling
clutch switch.

3. Faulty Powertrain
Control Module (PCM).

1. No refrigerant in the
refrigerant system.

2. Faulty fuse.

3. Faulty compressor
clutch coil.

4. Faulty compressor
clutch relay.

5. Faulty electronic cycling
clutch switch.

6. Faulty low pressure
cut-off switch.

7. Faulty high pressure
cut-off switch.

8. Faulty Powertrain
Control Module (PCM).

9. Faulty heater-A/C
control.

1. Excessive refrigerant oil
in system.

2. Temperature control
cable improperly installed
or faulty.

3. Blend-air door
inoperative, obstructed or
sealing improperly.

abnormal, suction pressure is not normal, see the A/C
Diagnosis chart in the Diagnosis and Testing section
of this group.

A/C Diagnosis

1. See Refrigerant System Leaks in the Diagnosis and
Testing section of this group. Test the refrigerant system for
leaks. Repair, evacuate and charge the refrigerant system, if
required.

2. See Electronic Cycling Clutch Switch in the Diagnosis and
Testing section of this group. Test the electronic cycling
clutch switch and replace, if required.

3. Refer to the proper Diagnostic Procedures manual for
testing of the PCM. Test the PCM and replace, if required.

1. See Refrigerant System Leaks in the Diagnosis and
Testing section of this group. Test the refrigerant system for
leaks. Repair, evacuate and charge the refrigerant system, if
required.

2. Check the fuses in the Power Distribution Center and the
junction block. Repair the shorted circuit or component and
replace the fuses, if required.

3. See Compressor Clutch Coil in the Diagnosis and Testing
section of this group. Test the compressor clutch coil and
replace, if required.

4. See Compressor Clutch Relay in the Diagnosis and
Testing section of this group. Test the compressor clutch
relay and relay circuits. Repair the circuits or replace the
relay, if required.

5. See Electronic Cycling Clutch Switch in the Diagnosis and
Testing section of this group. Test the electronic cycling
clutch switch and replace, if required.

6. See Low Pressure Cut-Off Switch in the Diagnosis and
Testing section of this group. Test the low pressure cut-off
switch and replace, if required.

7. See High Pressure Cut-Off Switch in the Diagnosis and
Testing section of this group. Test the high pressure cut-off
switch and replace, if required.

8. Refer to the proper Diagnostic Procedures manual for
testing of the PCM. Test the PCM and replace, if required.

9. See Heater-A/C Control in the Diagnosis and Testing
section of this group. Test the heater-A/C control and
replace, if required.

1. See Refrigerant Oil Level in the Service Procedures
section of this group. Recover the refrigerant from the
refrigerant system and inspect the refrigerant oil content.
Restore the refrigerant oil to the proper level, if required.

2. See Temperature Control Cable in the Removal and
Installation and Adjustments sections of this group. Inspect
the temperature control cable for proper routing, operation
and adjustment. Repair as required.

3. See Heater-A/C Housing Door in the Removal and
Installation section of this group. Inspect the blend-air door
for proper operation and sealing and correct, if required.

DN HEATING AND AIR CONDITIONING 24 - 15

DIAGNOSIS AND TESTING (Continued)

A/C Diagnosis

CONDITION POSSIBLE CAUSE CORRECTION

LOW SIDE PRESSURE IS
NORMAL OR SLIGHTLY
LOW, AND HIGH SIDE
PRESSURE IS TOO LOW.

LOW SIDE PRESSURE IS
NORMAL OR SLIGHTLY
HIGH, AND HIGH SIDE
PRESSURE IS TOO
HIGH.

LOW SIDE PRESSURE IS

TOO HIGH, AND HIGH
SIDE PRESSURE IS TOO
LOW.

LOW SIDE PRESSURE IS
TOO LOW, AND HIGH
SIDE PRESSURE IS TOO
HIGH.

1. Low refrigerant system
charge.

2. Refrigerant flow through
the evaporator coil is
restricted.

3. Faulty compressor.

1. Condenser air flow
restricted.

2. Inoperative cooling fan.

3. Faulty expansion valve.

4. Refrigerant system
overcharged.

5. Air in the refrigerant
system.

6. Engine overheating.

1. Accessory drive belt
slipping.

2. Faulty compressor.

1. Restricted refrigerant
flow through the
refrigerant lines.

2. Restricted refrigerant
flow through the
expansion valve.

3. Restricted refrigerant
flow through the
condenser.

4. Restricted refrigerant
flow through the filter-drier.

1. See Refrigerant System Leaks in the Diagnosis and
Testing section of this group. Test the refrigerant system for
leaks. Repair, evacuate and charge the refrigerant system, if
required.

2. See Evaporator Coil in the Removal and Installation
section of this group. Replace the restricted evaporator coil,
if required.

3. See Compressor in the Diagnosis and Testing section of
this group. Replace the compressor, if required.

1. Check the condenser for damaged fins, foreign objects
obstructing air flow through the condenser fins, and missing
or improperly installed air seals. Refer to Group 7 - Cooling
System for more information on air seals. Clean, repair, or
replace components as required.

2. Refer to Group 7 - Cooling System for more information.
Test the cooling fan and replace, if required.

3. See Expansion Valve in the Diagnosis and Tesing section
of this group. Replace the faulty expansion valve, if required.

4. See Refrigerant System Charge in the Service
Procedures section of this group. Recover the refrigerant
from the refrigerant system. Charge the refrigerant system to
the proper level, if required.

5. See Refrigerant System Leaks in the Diagnosis and
Testing section of this group. Test the refrigerant system for
leaks. Repair, evacuate and charge the refrigerant system, if
required.

6. Refer to Group 7 - Cooling System for more information.
Test the cooling system and repair, if required.

1. Refer to Group 7 - Cooling System for more information.
Inspect the accessory drive belt condition and tension.
Tighten or replace the accessory drive belt, if required.

2. See Compressor in the Diagnosis and Testing section of
this group. Replace the compressor, if required.

1. See Liquid Line and Suction and Discharge Line in the
Removal and Installation section of this group. Inspect the
refrigerant lines for kinks, tight bends or improper routing.
Correct the routing or replace the refrigerant line, if required.

2. See Expansion Valve in the Diagnosis and Testing section
of this group. Replace the restricted expansion valve, if
required.

3. See Condenser in the Removal and Installation section of
this group. Replace the restricted condenser, if required.

4. See Filter-Drier in the Removal and Installation section of
this group. Replace the restricted filter-drier, if required.

24 - 16 HEATING AND AIR CONDITIONING DN

DIAGNOSIS AND TESTING (Continued)

HEATER PERFORMANCE

Before performing the following tests, refer to
Group 7 - Cooling System for the procedures to check
the engine coolant level and flow, engine coolant
reserve/recovery system operation, accessory drive
belt condition and tension, radiator air flow and the
fan drive operation. Also be certain that the acces­sory vacuum supply line is connected at the engine
vacuum source.

MAXIMUM HEATER OUTPUT

Engine coolant is delivered to the heater core
through two heater hoses. With the engine idling at

Temperature Reference
Ambient Air Temperature
Minimum Heater System Air

Outlet Temperature

If the floor outlet air temperature is too low, refer
to Group 7 - Cooling System to check the engine cool­ant temperature specifications. Both of the heater
hoses should be hot to the touch. The coolant return
heater hose should be slightly cooler than the coolant
supply heater hose. If the return hose is much cooler
than the supply hose, locate and repair the engine
coolant flow obstruction in the cooling system. Refer
to Group 7 - Cooling System for the procedures.

An alternate method of checking heater perfor­mance is to use a DRB scan tool to monitor the

engine coolant temperature. The floor outlet air tem­perature reading should be no more than 4.5° C (40°
F) lower than the engine coolant temperature read­ing.

15.5° C
(60° F)

52.2° C

(126° F)

normal operating temperature, set the temperature
control knob in the full hot position, the mode control
switch knob in the floor position, and the blower
motor switch knob in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged at the heater-A/C housing
floor outlets. Compare the test thermometer reading
to the Temperature Reference chart.

21.1° C
(70° F)

56.1° C

(133° F)

OBSTRUCTED COOLANT FLOW

• Faulty water pump.

• Faulty thermostat.

• Pinched or kinked heater hoses.

• Improper heater hose routing.

• Plugged heater hoses or supply and return ports

at the cooling system connections.

• A plugged heater core.

If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is still
low, a mechanical problem may exist.

MECHANICAL PROBLEMS

Possible locations or causes of insufficient heat:

• An obstructed cowl air intake.

• Obstructed heater system outlets.

• A faulty, obstructed or improperly installed

blend-air door.

• The temperature control cable is not connected,

or is not routed or adjusted properly.

• A faulty blower system.

• A faulty heater-A/C control.

26.6° C
(80° F)

59.4° C

(139° F)

32.2° C
(90° F)

62.2° C

(144° F)

DN HEATING AND AIR CONDITIONING 24 - 17

DIAGNOSIS AND TESTING (Continued)

TEMPERATURE CONTROL

If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
heater-A/C control panel, the following could require
service:

• A faulty heater-A/C control.

Heater Diagnosis

CONDITION POSSIBLE CAUSE CORRECTION

INSUFFICIENT HEATER
OUTPUT.

1. Incorrect engine
coolant level.

2. Air trapped in engine
cooling system.

3. Incorrect engine
coolant temperature.

4. Temperature control
cable improperly installed
or not adjusted.

5. Blend-air door not
operating properly.

6. Insufficient air flow
through heater housing.

7. Improper blower motor
operation.

• The temperature control cable is not connected,

or is not routed or adjusted properly.

• A faulty, obstructed or improperly installed

blend-air door.

• An obstructed cowl air intake.

• The engine cooling system.

1. Check the engine coolant level. Refer to Group 7 ­Cooling System for the procedures.

2. Check the operation of the coolant reserve/recovery
system. Refer to Group 7 - Cooling System for the
procedures.

3. Check the performance and operation of the engine
cooling system including: thermostat, water pump, fan
drive, accessory drive belt, coolant flow (plugged radiator
or heater core, plugged or kinked coolant hoses), air flow
(missing or improperly installed radiator air seals or fan
shroud). Refer to Group 7 - Cooling System for the
procedures.

4. See Temperature Control Cable in the Removal and
Installation and in the Adjustments sections of this group.

5. Check for a damaged, obstructed or improperly
installed blend-air door or seals. See Heater-A/C Housing
Door in the Removal and Installation section of this
group.

6. Remove foreign material or obstructions from cowl air
intake.

7. See Blower Motor in the Diagnosis and Testing section
of this group.

HEATER-A/C CONTROL

Satisfactory heater and air conditioner perfor­mance depends upon proper operation and adjust­ment of all operating controls and refrigeration
system components. For circuit descriptions and dia­grams, refer to 8W-42 - Air Conditioning/Heater in
Group 8W - Wiring Diagrams. These inspections,
tests, and adjustments should be used to locate the
cause of a malfunction.

Operation must be tested as described in the fol­lowing sequence:

(1) Move the temperature control knob quickly to
the full hot and the full cold positions. There should
be a distinct sound of the blend-air door hitting its
stops within the heater-A/C housing at the end of
knob travel in each direction, with no spring-back of
the knob. If not OK, inspect the condition, routing,
installation and adjustment of the temperature con­trol cable. See Temperature Control Cable in the
Removal and Installation section and in the Adjust­ments section of this group for more information.

(2) Inspect and adjust the serpentine drive belt.
Refer to Group 7 - Cooling System for the procedures.

(3) Start the engine and hold the idle speed at

1,300 rpm.

(4) On vehicles with air conditioning, turn the
temperature control knob to the extreme counter­clockwise (Cool) position, and set the mode control
switch knob in the Bi-Level (A/C) position. The out­side (recirculation) air door should be open to outside
air. If not OK, see Vacuum System in the Diagnosis
and Testing section of this group.

(5) Open the vehicle windows. Test the blower
motor operation in all speeds. If not OK, see Blower
Motor in the Diagnosis and Testing section of this
group. Leave the blower motor switch knob in the
highest speed position.

(6) On vehicles with air conditioning, the compres­sor should be running and the air conditioning sys­tem in operation unless the ambient air temperature
is below about -1° C (30° F). If not OK, see A/C Per­formance in the Diagnosis and Testing section of this
group.

(7) Check the mode control switch operation. The
heater and air conditioner systems should respond as
described in the owner’s manual in the vehicle glove

24 - 18 HEATING AND AIR CONDITIONING DN

DIAGNOSIS AND TESTING (Continued)

box to each mode selected. Reduce the engine speed
to normal idle. The vacuum will be high at low idle
and the vacuum actuators should respond quickly. If
not OK, see Vacuum System in the Diagnosis and
Testing section of this group.

(8) If the vacuum tests, and the electrical compo­nent and circuit tests reveal no problems, disassem­ble the heater-A/C housing to inspect for mechanical
misalignment or binding of the mode doors.

VACUUM SYSTEM

Vacuum control is used to operate the mode doors
in the heater-A/C housing. Testing of the heater-A/C
mode control switch operation will determine if the
vacuum, electrical, and mechanical controls are func­tioning. However, it is possible that a vacuum control
system that operates perfectly at engine idle (high
engine vacuum) may not function properly at high
engine speeds or loads (low engine vacuum). This can
be caused by leaks in the vacuum system, or by a
faulty or improperly installed vacuum check valve.

A vacuum system test will help to identify the
source of poor vacuum system performance or vac­uum system leaks. Before starting this test, stop the
engine and make certain that the problem is not a
disconnected vacuum supply tube at the engine vac­uum source or at the vacuum reservoir.

Use an adjustable vacuum test set (Special Tool
C-3707) and a suitable vacuum pump to test the
heater-A/C vacuum control system. With a finger
placed over the end of the vacuum test hose probe
(Fig. 6), adjust the bleed valve on the test set gauge
to obtain a vacuum of exactly 27 kPa (8 in. Hg.).

Release and block the end of the probe several times
to verify that the vacuum reading returns to the
exact 27 kPa (8 in. Hg.) setting. Otherwise, a false
reading will be obtained during testing.

VACUUM CHECK VALVE

(1) Remove the vacuum check valve that is to be
tested. The valves are located in the vacuum supply
tube (black) at the power brake booster on the left
side of the engine compartment, and in the heater
and air conditioner vacuum take-out of the vacuum
supply tube in the engine compartment. The vacuum
check valve must be removed in order to perform the
following tests. See Vacuum Check Valve in the
Removal and Installation section of this group for the
procedures.

(2) Connect the test set vacuum supply hose to the
heater-A/C control side of the valve. When connected
to this side of the check valve, no vacuum should
pass and the test set gauge should return to the 27
kPa (8 in. Hg.) setting. If OK, go to step Step 4. If
not OK, replace the faulty valve.

(3) Connect the test set vacuum supply hose to the
engine vacuum side of the valve. When connected to
this side of the check valve, vacuum should flow
through the valve without restriction. If not OK,
replace the faulty valve.

HEATER-A/C CONTROLS

(1) Connect the test set vacuum probe to the heat­er-A/C vacuum supply (black) tube in the engine
compartment. Position the test set gauge so that it
can be viewed from the passenger compartment.

(2) Place the heater-A/C mode control switch knob
in each mode position, one position at a time, and
pause after each selection. The test set gauge should
return to the 27 kPa (8 in. Hg.) setting shortly after
each selection is made. If not OK, a component or
vacuum line in the vacuum circuit of the selected
mode has a leak. See Locating Vacuum Leaks in the
Diagnosis and Testing section of this group.

CAUTION: Do not use lubricant on the switch ports
or in the holes in the plug, as lubricant will ruin the
vacuum valve in the switch. A drop of clean water
in the connector plug holes will help the connector
slide onto the switch ports.

Fig. 6 Adjust Vacuum Test Bleed Valve

LOCATING VACUUM LEAKS

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

DN HEATING AND AIR CONDITIONING 24 - 19

DIAGNOSIS AND TESTING (Continued)

(1) Disconnect the vacuum harness connector from
the back of the heater-A/C mode control switch on
the instrument panel.

(2) Connect the test set vacuum hose probe to each
port in the vacuum harness connector, one port at a
time, and pause after each connection (Fig. 7). The
test set gauge should return to the 27 kPa (8 in. Hg.)
setting shortly after each connection is made. If OK,
replace the faulty heater-A/C control. If not OK, go to
Step 4.

Fig. 7 Vacuum Circuit Test

(3) Determine the vacuum line color of the vacuum
circuit that is leaking. To determine the vacuum line

colors, see the Vacuum Circuits chart (Fig. 8).

(4) Disconnect and plug the vacuum line from the
component (fitting, actuator, valve, switch, or reser­voir) on the other end of the leaking circuit. Instru­ment panel disassembly or removal may be necessary
to gain access to some components. See the Removal
and Installation section of this group for more infor­mation.

(5) Connect the test set hose or probe to the open
end of the leaking circuit. The test set gauge should
return to the 27 kPa (8 in. Hg.) setting shortly after
each connection is made. If OK, replace the faulty
disconnected component. If not OK, go to Step 7.

(6) To locate a leak in a vacuum line, leave one
end of the line plugged and connect the test set hose
or probe to the other end of the line. Run your fin­gers slowly along the line while watching the test set
gauge. The vacuum reading will fluctuate when your
fingers contact the source of the leak. To repair the
vacuum line, cut out the leaking section of the line.
Then, insert the loose ends of the line into a suitable
length of 3 millimeter (0.125 inch) inside diameter
rubber hose.

BLOWER MOTOR

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams. Possible causes of an inoperative front
or rear blower motor include:

• Faulty fuse (the rear blower motor fuse is
located in the relay and fuse block located on the
back of the junction block)

• Faulty blower motor circuit wiring or wire har­ness connectors

• Faulty blower motor resistor

• Faulty blower motor relay (front only)

• Faulty blower motor switch

• Faulty heater-A/C mode control switch (front

only)

• Faulty high speed blower motor relay (front
only)

• Faulty blower motor.

Possible causes of the front or rear blower motor

not operating in all speeds include:

• Faulty fuse (the rear blower motor fuse is
located in the relay and fuse block located on the
back of the junction block)

• Faulty blower motor switch

• Faulty blower motor resistor

• Faulty blower motor relay (front only)

• Faulty blower motor circuit wiring or wire har-

ness connectors

• Faulty high speed blower motor relay (front
only).

VIBRATION

Possible causes of front or rear blower motor vibra-

tion include:

• Improper blower motor mounting

• Improper blower wheel mounting

• Blower wheel out of balance or deformed

• Blower motor faulty.

NOISE

To determine that the rear blower is the source of
the noise, simply switch the blower motor from off to
on. There are no other moving parts involved in the
rear overhead A/C unit, which makes it simple to
identify the source of the noise. To verify that the
front blower is the source of the noise, unplug the

24 - 20 HEATING AND AIR CONDITIONING DN

DIAGNOSIS AND TESTING (Continued)

Fig. 8 Vacuum Circuits

DN HEATING AND AIR CONDITIONING 24 - 21

DIAGNOSIS AND TESTING (Continued)

front blower motor wire harness connector and oper­ate the heater-A/C system. If the noise goes away,
possible causes include:

• Foreign material in the heater-A/C housing

• Improper blower motor mounting

• Improper blower wheel mounting

• Blower motor faulty.

BLOWER MOTOR RELAY

RELAY TEST

The blower motor relay (Fig. 9) is located in the
Power Distribution Center (PDC). Remove the blower
motor relay from the PDC as described in this group
to perform the following tests:

(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.

(2) Resistance between terminals 85 and 86 (elec­tromagnet) should be 75 6 5 ohms. If OK, go to Step

4. If not OK, replace the faulty relay.

(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see Relay Circuit Test in the Diagno­sis and Testing section of this group. If not OK,
replace the faulty relay.

(2) The relay normally closed terminal cavity (87A)

is not used for this application. Go to Step 4.

(3) The relay normally open terminal cavity (87) is
connected to the blower motor. When the relay is
energized, terminal 87 is connected to terminal 30
and provides full battery current to the blower motor
feed circuit. There should be continuity between the
PDC cavity for terminal 87 and the blower motor
relay output circuit cavity of the blower motor wire
harness connector at all times. If OK, go to Step 5. If
not OK, repair the open circuit to the blower motor
as required.

(4) The coil battery terminal cavity (86) is con­nected to the ignition switch. When the ignition
switch is placed in the On position, fused ignition
switch output is directed from a fuse in the junction
block to the relay electromagnetic coil to energize the
relay. There should be battery voltage at the PDC
cavity for relay terminal 86 with the ignition switch
in the On position. If OK, go to Step 6. If not OK,
repair the open circuit to the junction block fuse as
required.

(5) The coil ground terminal cavity (85) is con­nected to ground. This terminal supplies the ground
for the relay electromagnetic coil. There should be
continuity between the PDC cavity for relay terminal
85 and a good ground at all times. If not OK, repair
the open circuit as required.

Fig. 9 Blower Motor Relay

RELAY CIRCUIT TEST

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams.

(1) The relay common feed terminal cavity (30) is
connected to fused battery feed directly from a fuse
in the Power Distribution Center (PDC), and should
be hot at all times. Check for battery voltage at the
PDC cavity for relay terminal 30. If OK, go to Step 3.
If not OK, repair the open circuit to the PDC fuse as
required.

BLOWER MOTOR RESISTOR

Both the front blower motor resistor and the
optional rear overhead A/C unit blower motor resistor
can be diagnosed using the procedure that follows.
For circuit descriptions and diagrams, refer to 8W-42

- Air Conditioning/Heater in Group 8W - Wiring Dia­grams.

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

(1) Disconnect and isolate the battery negative
cable.

(2) Unplug the wire harness connector from the
blower motor resistor.

(3) Check for continuity between each of the
blower motor switch input terminals of the resistor
and the resistor output terminal. In each case there
should be continuity. If OK, repair the wire harness
circuits between the blower motor switch and the

24 - 22 HEATING AND AIR CONDITIONING DN

DIAGNOSIS AND TESTING (Continued)

blower motor resistor or blower motor as required. If
not OK, replace the faulty blower motor resistor.

BLOWER MOTOR SWITCH

FRONT

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams.

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

(1) Check for battery voltage at the fuse in the
Power Distribution Center (PDC). If OK, go to Step

3. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.

(2) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the heater-A/C control from the instrument
panel. Check for continuity between the ground cir­cuit cavity of the heater-A/C control wire harness
connector and a good ground. There should be conti­nuity. If OK, go to Step 4. If not OK, repair the open
circuit to ground as required.

(3) With the heater-A/C control wire harness con-

nector unplugged, place the heater-A/C mode control
switch knob in any position except the Off position.
Check for continuity between the ground circuit ter­minal and each of the blower motor driver circuit ter­minals of the heater-A/C control as you move the
blower motor switch knob to each of the four speed
positions. There should be continuity at each driver
circuit terminal in only one blower motor switch
speed position. If OK, test and repair the blower
driver circuits between the heater-A/C control con­nector and the blower motor resistor as required. If
not OK, replace the faulty heater-A/C control unit.

REAR

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams.

(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the rear blower motor switch from the head­liner. Check for continuity between the ground circuit
cavity of the rear blower motor switch wire harness
connector and a good ground. There should be conti-

nuity. If OK, go to Step 3. If not OK, repair the open
circuit to ground as required.

(2) With the rear blower motor switch wire har­ness connector unplugged, place the rear blower
motor switch knob in any position except the Off
position. Check for continuity between the ground
circuit terminal and each of the blower motor driver
circuit terminals of the rear blower motor switch as
you move the blower motor switch knob to each of
the three speed positions. There should be continuity
at each driver circuit terminal in only one blower
motor switch speed position. If OK, test and repair
the rear blower driver circuits between the rear
blower motor switch wire harness connector and the
blower motor resistor as required. If not OK, replace
the faulty rear blower motor switch.

COMPRESSOR

When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu­tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
mounting brackets, or a loose compressor clutch
assembly.

Drive belts are speed sensitive. At different engine
speeds and depending upon belt tension, belts can
develop noises that are mistaken for a compressor
noise. Improper belt tension can cause a misleading
noise when the compressor clutch is engaged, which
may not occur when the compressor clutch is disen­gaged. Check the serpentine drive belt condition and
tension as described in Group 7 - Cooling System
before beginning this procedure.

(1) Select a quiet area for testing. Duplicate the
complaint conditions as much as possible. Switch the
compressor on and off several times to clearly iden­tify the compressor noise. Listen to the compressor
while the clutch is engaged and disengaged. Probe
the compressor with an engine stethoscope or a long
screwdriver with the handle held to your ear to bet­ter localize the source of the noise.

(2) Loosen all of the compressor mounting hard­ware and retighten. Tighten the compressor clutch
mounting nut. Be certain that the clutch coil is
mounted securely to the compressor, and that the
clutch plate and pulley are properly aligned and have
the correct air gap. See Compressor and Compressor
Clutch in the Removal and Installation section of this
group for the procedures.

(3) To duplicate a high-ambient temperature condi­tion (high head pressure), restrict the air flow

DN HEATING AND AIR CONDITIONING 24 - 23

DIAGNOSIS AND TESTING (Continued)

through the condenser. Install a manifold gauge set
to be certain that the discharge pressure does not
exceed 2760 kPa (400 psi).

(4) Check the refrigerant system plumbing for
incorrect routing, rubbing or interference, which can
cause unusual noises. Also check the refrigerant lines
for kinks or sharp bends that will restrict refrigerant
flow, which can cause noises. See Suction and Dis­charge Line in the Removal and Installation section
of this group for more information.

(5) If the noise is from opening and closing of the
high pressure relief valve, evacuate and recharge the
refrigerant system. See Refrigerant System Evacuate
and Refrigerant System Charge in the Service Proce­dures section of this group. If the high pressure relief
valve still does not seat properly, replace the com­pressor.

(6) If the noise is from liquid slugging on the suc­tion line, replace the filter-drier. See Filter-Drier in
the Removal and Installation section of this group for
the procedures. Check the refrigerant oil level and
the refrigerant system charge. See Refrigerant Oil
Level and Refrigerant System Charge in the Service
Procedures section of this group.

(7) If the noise continues, replace the compressor
and repeat Step 2.

COMPRESSOR CLUTCH COIL

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams. The battery must be fully-charged
before performing the following tests. Refer to Group
8A - Battery for more information.

(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.

(2) With the heater-A/C mode control switch in any
A/C mode, and the blower motor switch in the lowest
speed position, start the engine and run it at normal
idle.

(3) The compressor clutch coil voltage should read
within two volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within two volts of the battery voltage, test the
clutch coil feed circuit for excessive voltage drop and
repair as required. If there is no voltage reading at
the clutch coil, use a DRB scan tool and the proper
Diagnostic Procedures manual for testing of the com­pressor clutch circuit. The following components
must be checked and repaired as required before you
can complete testing of the clutch coil:

• Fuses in the junction block and the Power Dis-

tribution Center (PDC)

• Heater-A/C mode control switch

• Compressor clutch relay

• Electronic clutch cycling switch

• High pressure cut-off switch

• Low pressure cut-off switch

• Powertrain Control Module (PCM).

(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is 2.0 to 3.9
amperes with the electrical system voltage at 11.5 to

12.5 volts. This should only be checked with the work
area temperature at 21° C (70° F). If system voltage
is more than 12.5 volts, add electrical loads by turn­ing on electrical accessories until the system voltage
drops below 12.5 volts.

(a) If the clutch coil current reading is four
amperes or more, the coil is shorted and should be
replaced.

(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.

COMPRESSOR CLUTCH RELAY

RELAY TEST

The compressor clutch relay (Fig. 10) is located in

the Power Distribution Center (PDC). Refer to the
PDC label for relay identification and location.
Remove the relay from the PDC to perform the fol­lowing tests:

(1) A relay in the de-energized position should

have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.

(2) Resistance between terminals 85 and 86 (elec-

tromagnet) should be 75 6 5 ohms. If OK, go to Step

4. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.

There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see Relay Circuit Test in the Diagno­sis and Testing section of this group. If not OK,
replace the faulty relay.

RELAY CIRCUIT TEST

For circuit descriptions and diagrams, refer to

8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams.

(1) The relay common feed terminal cavity (30) is

connected to fused battery feed. There should be bat­tery voltage at the cavity for relay terminal 30 at all
times. If OK, go to Step 3. If not OK, repair the open
circuit to the fuse in the PDC as required.

(2) The relay normally closed terminal (87A) is not

used in this application. Go to Step 4.

(3) The relay normally open terminal cavity (87) is

connected to the compressor clutch coil. There should
be continuity between this cavity and the A/C com­pressor clutch relay output circuit cavity of the com­pressor clutch coil wire harness connector. If OK, go

24 - 24 HEATING AND AIR CONDITIONING DN

DIAGNOSIS AND TESTING (Continued)

the C2 circuit cavities in the body half of the elec­tronic cycling clutch switch wire harness connector
and the low pressure cut-off switch wire harness con­nector. There should be continuity. If OK, go to Step

4. If not OK, repair the open circuit as required.
(3) Plug in the wire harness connectors at the low

pressure cut-off and high pressure cut-off switches.
Connect the battery negative cable. Turn the ignition
switch in the On position. Check for battery voltage
at the fused ignition switch output (run) circuit cav­ity in the body half of the electronic cycling clutch
switch wire harness connector. If OK, go to Step 5. If
not OK, repair the open circuit to the junction block
as required.

(4) Plug in the wire harness connector at the elec-

tronic cycling clutch switch. With the ambient tem-

Fig. 10 Compressor Clutch Relay

to Step 5. If not OK, repair the open circuit as
required.

(4) The relay coil battery terminal (86) is con­nected to the fused ignition switch output (run/start)
circuit. There should be battery voltage at the cavity
for relay terminal 86 with the ignition switch in the
On position. If OK, go to Step 6. If not OK, repair the
open circuit to the fuse in the junction block as
required.

(5) The coil ground terminal cavity (85) is switched
to ground through the Powertrain Control Module
(PCM). There should be continuity between this cav­ity and the A/C compressor clutch relay control cir­cuit cavity of the PCM wire harness connector C
(gray) at all times. If not OK, repair the open circuit

as required.

perature from 20 to 30° C (68 to 90° F), start the
engine and set the heater-A/C mode control switch in
any A/C position. If the compressor clutch fails to
engage, use a DRB scan tool and the proper Diagnos­tic Procedures manual to check the Powertrain Con­trol Module (PCM) and its inputs and outputs. If the
compressor clutch engages, the clutch should cycle on
and off two to three times per minute. If the clutch
fails to cycle at this rate in these ambient tempera­tures, replace the faulty electronic cycling clutch
switch.

NOTE: If the ambient temperature is above 32° C
(90° F) the compressor clutch may stay engaged
and not cycle due to the high heat load. This con­dition is normal.

EXPANSION VALVE

ELECTRONIC CYCLING CLUTCH SWITCH (Front Unit Only)

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams. Use a volt/ohmmeter to test the elec­tronic cycling clutch switch. Verify that the
refrigerant system has the correct refrigerant charge.
Check that both the low and high pressure cut-off
switches are functional as described in the Diagnosis
and Testing section of this group before testing the
electronic cycling clutch switch.

(1) Disconnect and isolate the battery negative
cable. Unplug the wire harness connectors at the
electronic cycling clutch switch and the high pressure
cut-off switch. Check for continuity between the
C90A circuit cavities in the body half of the electronic
cycling clutch switch wire harness connector and the
high pressure cut-off switch wire harness connector.
There should be continuity. If OK, go to Step 3. If not
OK, repair the open circuit as required.

(2) Unplug the wire harness connector at the low
pressure cut-off switch. Check for continuity between

These tests must be made at an ambient tempera­ture of 21 to 29° C (70 to 85° F). Disconnect the wire
connector at the low pressure cut off switch. Use a
jumper wire to jumper terminals at the connector.

FRONT (ONLY)

(1) Attach a manifold gauge set. Close the vehicle
doors and windows, start the engine, and hold the
engine speed at 1,000 rpm. Set the heater-A/C mode
control switch knob in the recirculation mode (Max
A/C) position, the temperature control knob in the
full hot position, and the blower motor switch in the
highest speed position.

(2) Operate the air conditioning system for at least
five minutes to stabilize the system, and to provide
sufficient reheat to load the evaporator. The dis­charge pressure (high side) at the service port should
reach 966 to 1656 kPa (140 to 240 psi). If this dis­charge pressure cannot be obtained, check the refrig­erant system charge. See Refrigerant System Charge
in the Service Procedures section of this group.

DN HEATING AND AIR CONDITIONING 24 - 25

DIAGNOSIS AND TESTING (Continued)

WARNING: EXTREME CARE MUST BE USED WHEN
HANDLING LIQUID CARBON DIOXIDE (CO>

2>

), AS
SKIN INJURY CAN OCCUR. PROTECTIVE GLOVES
SHOULD BE WORN.

2>

(3) Apply liquid carbon dioxide (CO>

)tothe
expansion valve control head (completely cover the
head) for a minimum of thirty seconds. Observe the
manifold gauge set. The suction pressure (low side)
must drop to below 50 kPa (7.25 psi). If this reading
is not obtained, the expansion valve is faulty and
must be replaced.

(4) Remove the liquid carbon dioxide (CO>

2>

) from
the control head. Observe the manifold gauge set.
The suction pressure (low side) must increase to a
minimum of 262 kPa (38 psi), and then stabilize to a
pressure of 172 to 240 kPa (25 to 35 psi). If these
readings are not obtained, the expansion valve is
faulty and must be replaced.

(5) Set the engine idle speed at 1,000 rpm and the
blower motor switch in the highest speed position.
The suction pressure (low side) should be 138 to 207
kPa (20 to 30 psi). If the discharge pressure (high
side) is higher than 1656 kPa (240 psi), check for a
restricted discharge line. Also check the engine cool­ing system for overheating, air trapped in the sys­tem, or a faulty fan drive. If the discharge pressure
(high side) is less than 966 kPa (140 psi), check for a
faulty compressor.

FRONT AND REAR A/C

(1) Attach a manifold gauge set. Close the vehicle
doors and windows, start the engine, and hold the

engine speed at 1,000 rpm. Set the heater-A/C mode
control switch knob in the recirculation mode (Max
A/C) position, the temperature control knob in the
full hot position, and both the front and rear blower
motor switches in their highest speed positions.

(2) Operate the air conditioning system for at least
five minutes to stabilize the system, and to provide
sufficient reheat to load the front and rear evapora­tors. The discharge pressure (high side) at the service
port should reach 966 to 1656 kPa (140 to 240 psi). If
this discharge pressure cannot be obtained, check the
refrigerant system charge. See Refrigerant System
Charge in the Service Procedures section of this
group.

WARNING: EXTREME CARE MUST BE USED WHEN
HANDLING LIQUID CARBON DIOXIDE (CO>

2>

SKIN INJURY CAN OCCUR. PROTECTIVE GLOVES
SHOULD BE WORN.

(3) Both the front and rear expansion valves
should be checked for correct operation. Apply liquid
carbon dioxide (CO>2>) to the front expansion valve
control head (completely cover the head) for a mini-

)AS

mum of thirty seconds. Observe the manifold gauge
set. The suction pressure (low side) must drop to
below 50 kPa (7.25 psi). If this reading is not
obtained, the expansion valve is faulty and must be
replaced.

(4) Apply liquid carbon dioxide (CO>

2>

)tothe
front expansion valve control head (completely cover
the head) for a minimum of thirty seconds. Remove
the protective cover and apply liquid carbon dioxide

2>

(CO>

) to the rear expansion valve control head.
Grasp the suction line (large line) off the evaporator
with a bare hand and hold it for at least two min­utes. Use the same procedure with the front expan­sion valve. Grasp the suction line jumper below the
expansion valve (before the rear suction line tee)
with a bare hand and hold for at least two minutes.
When testing the front expansion valve, place the
rear blower motor switch in the Off position.

(5) With a correctly operating expansion valve, the
suction line will feel warm with the closing of the
valve (cold applied). Then the line will cool sharply
within two minutes as the valve opens. If this tem­perature change does not occur, the expansion valve
is faulty and must be replaced.

HIGH PRESSURE CUT-OFF SWITCH

Before performing diagnosis of the high pressure
cut-off switch, verify that the refrigerant system has
the correct refrigerant charge. See Refrigerant Sys­tem Charge in the Service Procedures section of this
group for more information.

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams.

(1) Disconnect and isolate the battery negative
cable.

(2) Unplug the high pressure cut-off switch wire
harness connector from the switch on the refrigerant
system fitting.

(3) Check for continuity between the two terminals
of the high pressure cut-off switch. There should be
continuity. If OK, test and repair the A/C switch
sense circuit as required. If not OK, replace the
faulty switch.

HIGH SPEED BLOWER MOTOR RELAY

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

24 - 26 HEATING AND AIR CONDITIONING DN

DIAGNOSIS AND TESTING (Continued)

RELAY TEST

The high speed blower motor relay (Fig. 11) is
located in the relay and fuse block, which is attached
to the back of the junction block, under the left side
of the instrument panel in the passenger compart­ment. Remove the high speed blower motor relay
from the relay and fuse block as described in this
group to perform the following tests:

(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.

(2) Resistance between terminals 85 and 86 (elec­tromagnet) should be 75 6 5 ohms. If OK, go to Step

4. If not OK, replace the faulty relay.

(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see Relay Circuit Test in the Diagno­sis and Testing section of this group. If not OK,
replace the faulty relay.

Fig. 11 Blower Motor Relay

RELAY CIRCUIT TEST

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams.

(1)

The relay common feed terminal cavity (30) is
connected to the ground side of the blower motor. There
should be continuity between the ground circuit cavity
of the blower motor wire harness connector and the
relay and fuse block cavity for relay terminal 30 at all
times. If OK, go to Step 3. If not OK, repair the open
circuit to the blower motor as required.

(2) The relay normally closed terminal cavity (87A)

is not used for this application. Go to Step 4.

(3) The relay normally open terminal cavity (87) is
connected to ground. When the relay is energized,
terminal 87 is connected to terminal 30 and provides
a direct path to ground for the blower motor. There
should be continuity between the relay and fuse

block cavity for terminal 87 and ground at all times.
If OK, go to Step 5. If not OK, repair the open circuit
to ground as required.

(4)

The coil battery terminal cavity (86) is connected
to the ignition switch. When the ignition switch is
placed in the On position, fused ignition switch output
is directed from a fuse in the junction block to the relay
electromagnetic coil to energize the relay. There should
be battery voltage at the relay and fuse block cavity for
relay terminal 86 with the ignition switch in the On
position. If OK, go to Step 6. If not OK, repair the open
circuit to the junction block fuse as required.

(5) The coil ground terminal cavity (85) is con­nected to the high speed output circuit terminal of
the blower motor switch. This terminal supplies the
ground for the relay electromagnetic coil. There
should be continuity between the relay and fuse
block cavity for relay terminal 85 and the high speed
output circuit terminal of the blower motor switch at
all times. If not OK, repair the open circuit to the
blower motor switch as required.

LOW PRESSURE CUT-OFF SWITCH

Before performing diagnosis of the low pressure
cut-off switch, remember that lower ambient temper­atures, below about -1° C (30° F), during cold
weather will open the switch contacts and prevent
compressor operation due to the pressure/tempera­ture relationship of the refrigerant.

Also verify that the refrigerant system has the cor­rect refrigerant charge. See Refrigerant System
Charge in the Service Procedures section of this
group for more information.

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir­ing Diagrams.

(1) Disconnect and isolate the battery negative
cable.

(2) Unplug the low pressure cut-off switch wire
harness connector from the switch on the suction line
jumper fitting.

Install a jumper wire between the two cavities of

(3)
the low pressure cut-off switch wire harness connector.

(4) Connect a manifold gauge set to the refrigerant
system service ports. See Refrigerant System Service
Equipment and Refrigerant System Service Ports in
the Description and Operation section of this group
for more information.

(5) Connect the battery negative cable.

(6) Place the heater-A/C mode control switch knob
in any A/C position and start the engine.

(7) Check for continuity between the two terminals
of the low pressure cut-off switch. There should be
continuity with a suction pressure (low side) reading
of 89.6 to 186.1 kPa (13 to 27 psi) or above, and no
continuity with a suction pressure reading of 68.9

DN HEATING AND AIR CONDITIONING 24 - 27

DIAGNOSIS AND TESTING (Continued)

kPa (10 psi) or below. If OK, test and repair the A/C
switch sense circuit as required. If not OK, replace
the faulty switch.

REFRIGERANT SYSTEM LEAKS

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE LEAK
TESTING THE SYSTEM.

If the air conditioning system does not cool prop­erly, the A/C system performance should be tested.
See A/C Performance in the Diagnosis and Testing
section of this group for the procedures. If the A/C
system refrigerant fill is found to be low or if the sys­tem is empty; a leak at a refrigerant line, connector
fitting, component, or component seal is likely.

An electronic leak detector designed for R-134a refrig­erant, or a fluorescent R-134a leak detection dye and a
black light are recommended for locating and confirm­ing refrigerant system leaks. Refer to the operating
instructions supplied by the equipment manufacturer
for the proper care and use of this equipment.

An oily residue on or near refrigerant system lines,
connector fittings, components, or component seals
can indicate the general location of a possible refrig­erant leak. However, the exact leak location should
be confirmed with an electronic leak detector prior to
component repair or replacement.

To detect a leak in the refrigerant system with an
electronic leak detector, perform one of the following
procedures:

instrument panel outlet and the floor duct outlet, or
near the outside of the rear overhead A/C unit outlet
bezel. Set the front or rear blower motor switch to
the lowest speed position, and the mode control
switch in the recirculation mode (Max-A/C).

SYSTEM LOW

(1) Position the vehicle in a wind-free work area.

This will aid in detecting small leaks.

(2) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run with the air conditioning system
turned on for five minutes.

(3) With the engine not running, use a electronic
R-134a leak detector and search for leaks. Because
R-134a refrigerant is heavier than air, the leak detec­tor probe should be moved slowly along the bottom
side of all refrigerant lines, connector fittings and
components.

CAUTION: Never insert a leak detector probe into
the outlet for the optional rear overhead A/C unit.
Failure to observe this caution could result in dam­age to the rear blower wheel and/or the leak detec­tor.

(4) To inspect the evaporator coil for leaks, insert
the electronic leak detector probe into the center
instrument panel outlet and the floor duct outlet, or
near the outside of the rear overhead A/C unit outlet
bezel. Set the front or rear blower motor switch to
the lowest speed position, and the mode control
switch in the recirculation mode (Max-A/C).

SYSTEM EMPTY

(1) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

Connect and dispense 0.283 kilograms (0.625

(2)
pounds or 10 ounces) of R-134a refrigerant into the
evacuated refrigerant system. See Refrigerant System
Charge in the Service Procedures section of this group.

(3) Position the vehicle in a wind-free work area.
This will aid in detecting small leaks.

With the engine not running, use a electronic

(4)
R-134a leak detector and search for leaks. Because
R-134a refrigerant is heavier than air, the leak detector
probe should be moved slowly along the bottom side of
all refrigerant lines, connector fittings and components.

CAUTION: Never insert a leak detector probe into the
outlet for the optional rear overhead A/C unit. Failure
to observe this caution could result in damage to the
rear blower wheel and/or the leak detector.

(5) To inspect the evaporator coil for leaks, insert
the electronic leak detector probe into the center

SERVICE PROCEDURES

REFRIGERANT RECOVERY

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE
RECOVERING REFRIGERANT.

A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to recover the refrigerant from an R-134a refrig­erant system. Refer to the operating instructions sup­plied by the equipment manufacturer for the proper
care and use of this equipment.

REFRIGERANT SYSTEM EVACUATE

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE EVAC­UATING THE SYSTEM.

24 - 28 HEATING AND AIR CONDITIONING DN

SERVICE PROCEDURES (Continued)

If the refrigerant system has been open to the atmo­sphere, it must be evacuated before the system can be
charged. If moisture and air enters the system and
becomes mixed with the refrigerant, the compressor
head pressure will rise above acceptable operating lev­els. This will reduce the performance of the air condi­tioner and damage the compressor. Evacuating the
refrigerant system will remove the air and boil the
moisture out of the system at near room temperature.
To evacuate the refrigerant system, use the following
procedure:

(1) Connect a R-134a refrigerant recovery/recy­cling/charging station that meets SAE Standard
J2210 and a manifold gauge set to the refrigerant
system of the vehicle.

(2) Open the low and high side valves and start
the charging station vacuum pump. When the suc­tion gauge reads 88 kPa (26 in. Hg.) vacuum or
greater, close all of the valves and turn off the vac­uum pump.

If the refrigerant system fails to reach the spec-

(a)
ified vacuum, the system has a leak that must be cor­rected. See Refrigerant System Leaks in the
Diagnosis and Testing section of this group for the
procedures.

(b) If the refrigerant system maintains the spec­ified vacuum for five minutes, restart the vacuum
pump, open the suction and discharge valves and
evacuate the system for an additional ten minutes.
(3) Close all of the valves, and turn off the charg-

ing station vacuum pump.

(4) The refrigerant system is now ready to be

charged with R-134a refrigerant. See Refrigerant

System Charge in the Service Procedures section of
this group.

REFRIGERANT SYSTEM CHARGE

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE
CHARGING THE REFRIGERANT SYSTEM.

After the refrigerant system has been tested for leaks

and evacuated, a refrigerant charge can be injected into
the system. See Refrigerant Charge Capacity in the Ser­vice Procedures section of this group for the proper
amount of the refrigerant charge.

A R-134a refrigerant recovery/recycling/charging

station that meets SAE Standard J2210 must be
used to charge the refrigerant system with R-134a
refrigerant. Refer to the operating instructions sup­plied by the equipment manufacturer for the proper
care and use of this equipment.

REFRIGERANT CHARGE CAPACITY

The R-134a refrigerant system charge capacity for
this vehicle is: Dual Unit: 0.850 kilograms (30 ounc­es), Single Unit: 0.793 kilograms (28 ounces).

REFRIGERANT OIL LEVEL

When an air conditioning system is assembled at
the factory, all components except the compressor are
refrigerant oil free. After the refrigerant system has
been charged and operated, the refrigerant oil in the
compressor is dispersed throughout the refrigerant
system. The evaporator, filter-drier, condenser, and
compressor will each retain a significant amount of
the needed refrigerant oil.

It is important to have the correct amount of oil in
the refrigerant system. This ensures proper lubrica­tion of the compressor. Too little oil will result in
damage to the compressor. Too much oil will reduce
the cooling capacity of the air conditioning system.

It will not be necessary to check the oil level in the
compressor or to add oil, unless there has been an oil
loss. An oil loss may occur due to a rupture or leak from
a refrigerant line, a connector fitting, a component, or a
component seal. If a leak occurs, add 30 milliliters (1
fluid ounce) of refrigerant oil to the refrigerant system
after the repair has been made. Refrigerant oil loss will
be evident at the leak point by the presence of a wet,
shiny surface around the leak.

Refrigerant oil must be added when a filter-drier,
evaporator coil, or condenser are replaced. See the
Refrigerant Oil Capacities chart. When a compressor
is replaced, the refrigerant oil must be drained from
the old compressor and measured. Drain all of the
refrigerant oil from the new compressor, then fill the
new compressor with the same amount of refrigerant
oil that was drained out of the old compressor.

Refrigerant Oil Capacities

Component ml fl oz

A/C System (Front Only) 165 5.5

A/C System (Front & Rear) 240 8

Filter-Drier 30 1
Condenser 30 1

Evaporator (Front) 60 2

Evaporator (Rear) 30 1

drain and measure

Compressor

the oil from the old
compressor - see
text.

DN HEATING AND AIR CONDITIONING 24 - 29

REMOVAL AND INSTALLATION

REFRIGERANT LINE COUPLER

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(2) Remove the secondary clip from the spring-lock
coupler.

(3) Fit the proper size A/C line disconnect tool
(Special Tool Kit 7193) over the spring-lock coupler
cage (Fig. 12).

NOTE: The garter spring may not release if the A/C
line disconnect tool is cocked while pushing it into
the coupler cage opening.

(6) Open and remove the A/C line disconnect tool

from the disconnected spring-lock coupler.

(7) Complete the separation of the two halves of

the coupler fitting.

INSTALLATION

(1) Check to ensure that the garter spring is
located within the cage of the male coupler fitting,
and that the garter spring is not damaged.

(a) If the garter spring is missing, install a new

spring by pushing it into the coupler cage opening.

(b) If the garter spring is damaged, remove it
from the coupler cage with a small wire hook (DO
NOT use a screwdriver) and install a new garter
spring.
(2) Clean any dirt or foreign material from both

halves of the coupler fitting.

(3) Install new O-rings on the male half of the cou-

pler fitting.

CAUTION: Use only the specified O-rings as they
are made of a special material for the R-134a sys­tem. The use of any other O-rings may allow the
connection to leak intermittently during vehicle
operation.

Fig. 12 Refrigerant Line Spring-Lock Coupler

Disconnect

(4) Close the two halves of the A/C line disconnect

tool around the spring-lock coupler.

(5) Push the A/C line disconnect tool into the open
side of the coupler cage to expand the garter spring.
Once the garter spring is expanded and while still
pushing the disconnect tool into the open side of the
coupler cage, pull on the refrigerant line attached to
the female half of the coupler fitting until the flange
on the female fitting is separated from the garter
spring and cage on the male fitting within the dis­connect tool.

(4) Lubricate the male fitting and O-rings, and the
inside of the female fitting with clean R-134a refrig­erant oil. Use only refrigerant oil of the type recom­mended for the compressor in the vehicle.

(5) Fit the female half of the coupler fitting over
the male half of the fitting.

(6) Push together firmly on the two halves of the
coupler fitting until the garter spring in the cage on
the male half of the fitting snaps over the flanged
end on the female half of the fitting.

(7) Ensure that the spring-lock coupler is fully
engaged by trying to separate the two coupler halves.
This is done by pulling the refrigerant lines on either
side of the coupler away from each other.

(8) Reinstall the secondary clip over the spring­lock coupler cage.

HIGH PRESSURE CUT-OFF SWITCH

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Unplug the wire harness connector from the
high pressure cut-off switch, which is mounted to a
fitting on the discharge line between the compressor
and the condenser inlet (Fig. 13).

24 - 30 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

of the refrigerant system connections is pressure-tight
and leak free. It is a good practice to inspect all flexible
hose refrigerant lines at least once a year to make sure
they are in good condition and properly routed.

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) Unplug the wire harness connector from the
high pressure cut-off switch.

Disconnect the refrigerant line couplers at the

(4)
condenser and the suction line jumper. See Refrigerant
Line Coupler in the Removal and Installation section of

Fig. 13 High Pressure Cut-Off Switch Remove/Install

(3) Unscrew the high pressure cut-off switch from

the discharge line fitting.

(4) Remove the high pressure cut-off switch from

the vehicle.

(5) Remove the O-ring seal from the discharge line

fitting and discard.

this group for the procedures. Install plugs in, or tape
over all of the opened refrigerant line fittings.

(5) Remove the nut that secures the refrigerant
line support bracket near the compressor.

(6) Remove the screw that secures the refrigerant
line manifold to the compressor (Fig. 14). Install
plugs in, or tape over all of the opened refrigerant
line fittings.

INSTALLATION

(1) Lubricate a new O-ring seal with clean refrig-

erant oil and install it on the discharge line fitting.
Use only the specified O-rings as they are made of a
special material for the R-134a system. Use only
refrigerant oil of the type recommended for the com­pressor in the vehicle.

(2) Install and tighten the high pressure cut-off

switch on the discharge line fitting.

(3) Plug the wire harness connector into the high

pressure cut-off switch.

(4) Connect the battery negative cable.

SUCTION AND DISCHARGE LINE

Any kinks or sharp bends in the refrigerant plumb­ing will reduce the capacity of the entire air condi­tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.

High pressures are produced in the refrigerant sys­tem when the air conditioning compressor is operating.
Extreme care must be exercised to make sure that each

Fig. 14 Suction and Discharge Line Remove/Install -

Typical

(7) Remove the suction and discharge line assem-

bly from the vehicle.

DN HEATING AND AIR CONDITIONING 24 - 31

REMOVAL AND INSTALLATION (Continued)

INSTALLATION

(1) Remove the tape or plugs from all of the refrig­erant line fittings. Install the refrigerant line cou­plers to the condenser and the suction line jumper.
See Refrigerant Line Coupler in the Removal and
Installation section of this group for the procedures.

(2) Install the refrigerant line manifold to the com­pressor. Tighten the mounting screw to 22 N·m (200
in. lbs.).

(3) Install the nut that secures the refrigerant line
support bracket near the compressor.

(4) Plug in the wire harness connector to the high
pressure cut-off switch.

(5) Connect the battery negative cable.

(6) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(7) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

COMPRESSOR

The compressor may be removed and repositioned
without disconnecting the refrigerant lines or dis­charging the refrigerant system. Discharging is not
necessary if servicing the compressor clutch or clutch
coil, the engine, the cylinder head, or the generator.

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(2)

Disconnect and isolate the battery negative cable.

(3) Remove the serpentine drive belt. Refer to
Group 7 - Cooling System for the procedures.

(4) Unplug the compressor clutch coil wire harness
connector.

(5) Remove the suction and discharge refrigerant
line manifold from the compressor. See Suction and
Discharge Line in the Removal and Installation sec­tion of this group for the procedures. Install plugs in,
or tape over all of the opened refrigerant fittings.

(6) Remove the four screws that secure the com­pressor to the mounting bracket (Fig. 15).

(7) Remove the compressor from the mounting
bracket.

Fig. 15 Compressor Remove/Install - Typical

24 - 32 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

INSTALLATION

NOTE: If a replacement compressor is being installed,
be certain to check the refrigerant oil level. See Refrig­erant Oil Level in the Service Procedures section of
this group. Use only refrigerant oil of the type recom­mended for the compressor in the vehicle.

(1)

Install the compressor to the mounting bracket.

Tighten the four mounting screws to 27 N·m (20 ft. lbs.).

(2) Remove the tape or plugs from all of the
opened refrigerant line fittings. Install the suction
and discharge line manifold to the compressor. See
Suction and Discharge Line in the Removal and
Installation section of this group for the procedures.

(3) Install the serpentine drive belt. Refer to
Group 7 - Cooling System for the procedures.

(4) Plug in the compressor clutch coil wire harness
connector.

(5) Connect the battery negative cable.

(6) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(7) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

clutch plate. Hold the clutch plate stationary and
remove the hex nut (Fig. 16).

(5) Remove the clutch plate and the clutch shims.
(6) Remove the external front housing snap ring

with snap ring pliers (Fig. 17).

COMPRESSOR CLUTCH

The refrigerant system can remain fully-charged
during compressor clutch, pulley, or coil replacement.
The compressor clutch can be serviced in the vehicle.

REMOVAL

(1)

Disconnect and isolate the battery negative cable.

(2) Remove the serpentine drive belt. Refer to
Group 7 - Cooling System for the procedures.

(3) Unplug the compressor clutch coil wire harness
connector.

(4) Insert the two pins of the spanner wrench
(Special Tool 6462 in Kit 6460) into the holes of the

Fig. 17 External Snap Ring Remove

(7) Install the lip of the rotor puller (Special Tool
C-6141-1 in Kit 6460) into the snap ring groove
exposed in Step 7, and install the shaft protector
(Special Tool C-6141-2 in Kit 6460) (Fig. 18).

Fig. 16 Clutch Nut Remove

Fig. 18 Shaft Protector and Puller

DN HEATING AND AIR CONDITIONING 24 - 33

REMOVAL AND INSTALLATION (Continued)

(8) Install the puller through-bolts (Special Tool
C-6461) through the puller flange and into the jaws
of the rotor puller and tighten (Fig. 19). Turn the
puller center bolt clockwise until the rotor pulley is
free.

(10) Remove the snap ring from the compressor
hub and remove the clutch field coil (Fig. 21). Slide
the clutch field coil off of the compressor hub.

Fig. 19 Install Puller Plate

(9) Remove the screw and retainer from the clutch
coil lead wire harness on the compressor front hous­ing (Fig. 20).

Fig. 20 Clutch Coil Lead Wire Harness

Fig. 21 Clutch Field Coil Snap Ring Remove

INSPECTION

Examine the friction surfaces of the clutch pulley
and the front plate for wear. The pulley and front
plate should be replaced if there is excessive wear or
scoring.

If the friction surfaces are oily, inspect the shaft
and nose area of the compressor for oil. Remove the
felt from the front cover. If the felt is saturated with
oil, the shaft seal is leaking and the compressor must
be replaced.

Check the clutch pulley bearing for roughness or
excessive leakage of grease. Replace the bearing, if
required.

INSTALLATION

(1) Install the clutch field coil and snap ring.

(2) Install the clutch coil lead wire harness retain­ing clip on the compressor front housing and tighten
the retaining screw.

(3) Align the rotor assembly squarely on the front
compressor housing hub.

(4) Thread the handle (Special Tool 6464 in Kit

6460) into the driver (Special Tool 6143 in Kit 6460)
(Fig. 22).

(5) Place the driver tool assembly into the bearing
cavity on the rotor. Make certain the outer edge of
the tool rests firmly on the rotor bearing inner race
(Fig. 23).

(6) Tap the end of the driver while guiding the
rotor to prevent binding. Tap until the rotor bottoms

24 - 34 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

(8) Install the original clutch shims on the com­pressor shaft.

(9) Install the clutch plate. Use the shaft protector
(Special Tool 6141-2 in Kit 6460) to install the clutch
plate on the compressor shaft (Fig. 24). Tap the
clutch plate over the compressor shaft until it has
bottomed against the clutch shims. Listen for a dis­tinct change of sound during the tapping process, to
indicate the bottoming of the clutch plate.

Fig. 22 Rotor Installer Set

Fig. 23 Rotor Install

against the compressor front housing hub. Listen for
a distinct change of sound during the tapping pro­cess, to indicate the bottoming of the rotor.

(7) Install the external front rotor snap ring with
snap ring pliers. The bevel side of the snap ring must
be facing outward. Press the snap ring to make sure
it is properly seated in the groove.

CAUTION: If the snap ring is not fully seated in the
groove it will vibrate out, resulting in a clutch fail­ure and severe damage to the front housing of the
compressor.

Fig. 24 Clutch Plate Install

(10) Replace the compressor shaft hex nut. Tighten

the nut to 14.4 N·m (10.5 ft. lbs.).

(11) Check the clutch air gap with a feeler gauge
(Fig. 25). If the air gap does not meet the specifica­tion, add or subtract shims as required. The air gap
specification is 0.41 to 0.79 millimeter (0.016 to 0.031
inch). If the air gap is not consistent around the cir­cumference of the clutch, lightly pry up at the mini­mum variations. Lightly tap down at the points of
maximum variation.

NOTE: The air gap is determined by the spacer
shims. When installing an original, or a new clutch
assembly, try the original shims first. When install­ing a new clutch onto a compressor that previously
did not have a clutch, use 1.0, 0.50, and 0.13 milli­meter (0.040, 0.020, and 0.005 inch) shims from the
clutch hardware package that is provided with the
new clutch.

(12) Reverse the remaining removal procedures to
complete the installation.

CLUTCH BREAK-IN

After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty

DN HEATING AND AIR CONDITIONING 24 - 35

REMOVAL AND INSTALLATION (Continued)

(7) Connect the battery negative cable.

(8) Test the relay operation.

LOW PRESSURE CUT-OFF SWITCH

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Unplug the wire harness connector from the
low pressure cut-off switch on the suction line jumper
near the expansion valve (Fig. 27).

Fig. 25 Check Clutch Air Gap

times (five seconds on, then five seconds off). During
this procedure, set the heater-A/C control to the
recirculation mode (Max-A/C), the blower motor
switch in the highest speed position, and the engine
speed at 1500 to 2000 rpm. This procedure (burnish­ing) will seat the opposing friction surfaces and pro­vide a higher compressor clutch torque capability.

COMPRESSOR CLUTCH RELAY

(1) Disconnect and isolate the battery negative

cable.

(2) Remove the cover from the Power Distribution

Center (PDC) (Fig. 26).

Fig. 26 Power Distribution Center

(3) Refer to the label on the PDC for compressor

clutch relay identification and location.

(4) Unplug the compressor clutch relay from the

PDC.

(5) Install the compressor clutch relay by aligning
the relay terminals with the cavities in the PDC and
pushing the relay firmly into place.

(6) Install the PDC cover.

Fig. 27 Low Pressure Cut-Off Switch Remove/Install

(3) Unscrew the low pressure cut-off switch from

the fitting on the suction line jumper.

(4) Remove the O-ring seal from the suction line

jumper fitting and discard.

INSTALLATION

(1) Lubricate a new O-ring seal with clean refrig­erant oil and install it on the suction line jumper fit­ting. Use only the specified O-rings as they are made
of a special material for the R-134a system. Use only
refrigerant oil of the type recommended for the com­pressor in the vehicle.

(2) Install and tighten the low pressure cut-off
switch on the suction line jumper fitting. The switch
should be hand-tightened onto the fitting.

(3) Plug the wire harness connector into the low
pressure cut-off switch.

(4) Connect the battery negative cable.

24 - 36 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

ELECTRONIC CYCLING CLUTCH SWITCH

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Unplug the wire harness connector from the
electronic cycling clutch switch near the expansion
valve (Fig. 28).

Fig. 28 Electronic Cycling Clutch Switch Remove/

Install

(3) Remove and discard the fastener that secures
the electronic cycling clutch switch to the outboard
side of the expansion valve.

(4) Pull the electronic cycling clutch switch away
from the side of the expansion valve far enough for
the thermistor probe capillary tube to clear the well

in the expansion valve. The washer bottle may have
to be removed.

NOTE: The capillary tube well in the expansion
valve is filled with a special thermally-conductive
grease. This grease should be removed from the
old parts and reused on the new parts whenever
the electronic cycling clutch switch or the expan­sion valve are replaced.

INSTALLATION

(1) Insert the thermistor probe capillary tube of
the electronic cycling clutch switch into the well on
the outboard side of the expansion valve.

(2) Install the electronic cycling clutch switch to
the expansion valve and secure it with a new fas­tener.

(3) Plug the wire harness connector into the elec­tronic cycling clutch switch.

(4) Connect the battery negative cable.

LIQUID LINE

Any kinks or sharp bends in the refrigerant plumb­ing will reduce the capacity of the entire air condi­tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. High pressures are
produced in the refrigerant system when the air con­ditioning compressor is operating. Extreme care must
be exercised to make sure that each of the refriger­ant system connections is pressure-tight and leak
free.

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

FRONT

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) Remove the screw that secures the front liquid
line block fitting to the inlet of the filter-drier, and
disengage the fitting from the filter-drier (Fig. 29).
Install plugs in, or tape over all of the opened refrig­erant line fittings.

(4) Disconnect the front liquid line refrigerant line
coupler at the condenser outlet. See Refrigerant Line
Coupler in the Removal and Installation section of
this group for the procedures. Install plugs in, or
tape over all of the opened refrigerant line fittings.

(5) Remove the front liquid line from the engine
compartment.

INSTALLATION

(1) Remove the tape or plugs from the refrigerant
line fittings on the front liquid line and the con­denser outlet. Connect the front liquid line to the
condenser outlet. See Refrigerant Line Coupler in the
Removal and Installation section of this group for the
procedures.

(2) Remove the tape or plugs from the front liquid
line block fitting and the filter-drier inlet. Install the
front liquid line block fitting to the filter-drier inlet
and secure the connection with a screw. Tighten the
mounting screw to 13.5 N·m (120 in. lbs.).

(3) Connect the battery negative cable.

(4) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(5) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

DN HEATING AND AIR CONDITIONING 24 - 37

REMOVAL AND INSTALLATION (Continued)

Fig. 29 Liquid Line Remove/Install

REAR

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Recover the refrigerant from the refrigerant

system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) Remove the engine air filter housing. Refer to

Group 14 - Fuel System for the procedures.

(4) Remove the screw that secures the ground
strap to the inboard side of the rear liquid line block
fitting.

(5) Remove the screw that secures the rear liquid
line block fitting to the outlet of the filter-drier, and
disengage the fitting from the filter-drier. Install
plugs in, or tape over all of the opened refrigerant
line fittings.

(6) Disconnect the suction line from the suction
jumper. See refrigerant line coupler in the removal
and installation section.

(7) If the vehicle is equipped with the optional rear
overhead A/C unit, disconnect the refrigerant line
couplers near the dash panel between the suction
line jumper and the rear liquid line extension and
both of the underbody refrigerant lines. See Refriger­ant Line Coupler in the Removal and Installation
section of this group for the procedures. Install plugs
in, or tape over all of the opened refrigerant line fit­tings.

(8) Disengage the clip that secures the rear liquid

line to the inner fender shield.

(9) Remove the nut that secures the rear liquid
line block fitting to the stud on the expansion valve,
and disengage the fitting from the expansion valve.
Install plugs in, or tape over all of the opened refrig­erant line fittings.

(10) Remove the rear liquid line from the engine
compartment.

(11) Remove the suction line jumper from the rear
liquid line block fitting. See Suction Line Jumper in
the Removal and Installation section of this group for
the procedures.

INSTALLATION

(1) Install the suction line jumper into the rear liq­uid line block fitting. See Suction Line Jumper in the
Removal and Installation section of this group for the
procedures.

(2) Remove the tape or plugs from the rear liquid
line block fitting and the expansion valve. Install the
rear liquid line block fitting over the expansion valve
stud and secure the connection with a nut. Tighten
the mounting nut to 22.5 N·m (200 in. lbs.).

(3) Install the rear liquid line in the clip on the
inner fender shield.

(4) If the vehicle is equipped with the optional rear
overhead A/C unit, remove the tape or plugs from the
refrigerant line fittings on the suction line jumper
and the rear liquid line extension and both of the

24 - 38 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

underbody refrigerant lines. Connect the underbody
refrigerant lines to the suction line jumper and the
rear liquid line extension. See Refrigerant Line Cou­pler in the Removal and Installation section of this
group for the procedures.

(5) Remove the tape or plugs from the rear liquid
line block fitting and the filter-drier outlet. Install
the rear liquid line block fitting to the filter-drier
outlet and secure the connection with a screw.
Tighten the mounting screw to 13.5 N·m (120 in.
lbs.). Connect the suction line from the suction dis­charge assembly to the suction jumper tube.

(6) Reinstall the screw that secures the ground
strap to the inboard side of the rear liquid line block
fitting. Tighten the mounting screw to 11.9 N·m (105
in. lbs.).

(7) Reinstall the engine air filter housing. Refer to
Group 14 - Fuel System for the procedures.

(8) Connect the battery negative cable.

(9) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(10) Charge the refrigerant system. See Refriger­ant System Charge in the Service Procedures section
of this group.

SUCTION LINE JUMPER

Any kinks or sharp bends in the refrigerant plumb­ing will reduce the capacity of the entire air condi­tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. High pressures are
produced in the refrigerant system when the air con­ditioning compressor is operating. Extreme care must

be exercised to make sure that each of the refriger­ant system connections is pressure-tight and leak
free.

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

plugs in, or tape over all of the opened refrigerant
line fittings.

(5) Remove the rear liquid line from the engine
compartment. See Liquid Line in the Removal and
Installation section of this group for the procedures.

(6) Slide the plastic retainer that secures the suc­tion line jumper out of the saddle formation at the
top of the rear liquid line block fitting. Secure block,
preferably in a vise. Tap the plastic retainer out with
a hammer and flat-bladed screwdriver.

(7) Remove the suction line jumper from the rear
liquid line block fitting.

INSTALLATION

(1) Using a new O-ring, install the suction line
jumper into the saddle formation at the top of the
rear liquid line block fitting.

(2) Slide the plastic retainer that secures the suc­tion line jumper into the rear liquid line block fitting.

(3) Install the rear liquid line into the engine com­partment. See Liquid Line in the Removal and
Installation section of this group for the procedures.

(4) Remove the tape or plugs from the refrigerant
line fittings on the suction line and the suction line
jumper. Install the suction line to the suction line
jumper. See Refrigerant Line Coupler in the Removal
and Installation section of this group for the proce­dures.

(5) Install the low pressure cut-off switch to the
fitting on the suction line jumper. See Low Pressure
Cut-Off Switch in the Removal and Installation sec­tion of this group for the procedures.

(6) Connect the battery negative cable.

(7) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(8) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

EXPANSION VALVE

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Remove the low pressure cut-off switch from
the fitting on the suction line jumper. See Low Pres­sure Cut-Off Switch in the Removal and Installation
section of this group for the procedures.

(3) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(4) Disconnect the refrigerant line coupler between
the suction line and the suction line jumper. See
Refrigerant Line Coupler in the Removal and Instal­lation section of this group for the procedures. Install

FRONT

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

DN HEATING AND AIR CONDITIONING 24 - 39

REMOVAL AND INSTALLATION (Continued)

(3) Remove the rear liquid line from the engine
compartment. See Liquid Line in the Removal and
Installation section of this group for the procedures.

(4) Remove the electronic cycling clutch switch
from the outboard side of the expansion valve. See
Electronic Cycling Clutch Switch in the Removal and
Installation section of this group for the procedures.

(5) Remove the two screws that secure the expan­sion valve to the evaporator tube mounting flange
(Fig. 30).

REAR

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) Remove the engine air filter housing. Refer to
Group 14 - Fuel System for the procedures.

(4) Remove the underbody line. See Underbody
Refrigerant Line in the Removal and Installation sec­tion of this group for the procedures. Remove the line
from the vehicle and install plugs in, or tape over, all
of the open refrigerant fittings.

(5) Disassemble the bolt (M6) from the forward
(longer) section of the underbody lines to the valve.
Install plugs in, or tape over the open refrigerant fit­tings.

Fig. 30 Expansion Valve Remove/Install

(6) Remove the expansion valve from the evapora-

tor tube mounting flange. Install plugs in, or tape

over all of the opened refrigerant line fittings.

INSTALLATION

(1) Remove the tape or plugs from the evaporator
tubes and the evaporator tube mounting flange side
of the expansion valve. Install the expansion valve to
the evaporator tube mounting flange and secure with
two screws. Tighten the mounting screws to 11.4 N·m
(100 in. lbs.).

(2) Reinstall the electronic cycling clutch switch to
the outboard side of the expansion valve. See Elec­tronic Cycling Clutch Switch in the Removal and
Installation section of this group for the procedures.

(3) Reinstall the rear liquid line to the engine com­partment. See Liquid Line in the Removal and
Installation section of this group for the procedures.

(4) Connect the battery negative cable.

(5) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(6) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

Fig. 31 REAR EXPANSION VALVE REMOVAL/

INSTALL

(6) Disassemble the two bolts attaching the expan­sion valve to the rearward (shorter) section of the
underbody lines. Install plugs in, or tape over the
open refrigerant fittings.

24 - 40 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

INSTALLATION

(1) Remove the tape or plugs from expansion valve
and the rearward (shorter) section of the underbody
lines. Align the expansion valve ports with the block
fitting on the rearward lines and assemble with the
two bolts.

(2) Remove the tape or plugs from the forward
(longer) section of the underbody lines. Align the
expansion valve ports and stud with the block fitting
on the forward lines. Secure with the mounting bolt.

(3) Install the underbody refrigerant lines. See
Underbody Refrigerant Line in the Removal and
Installation section of this group.

(4) Install the engine air filter housing. Refer to
Group 14 - Fuel System for the procedures.

(5) Evacuate and charge the refrigerant system.
See Refrigerant System Evacuate in the Service Pro­cedures section of this group.

(6) Connect the battery negative cable.

Fig. 32 Filter-Drier Remove/Install

FILTER-DRIER

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro-

cedures section of this group.

(3) Remove the screws that secure the front and
rear liquid line block fittings to the filter-drier inlet
and outlet (Fig. 32). Disengage the block fittings from
the filter-drier. Install plugs in, or tape over all of the
opened refrigerant line fittings.

(4) Remove the screw that secures the filter-drier
mounting bracket to the front fender wheelhouse
front extension.

(5) Remove the filter-drier from the engine com­partment.

INSTALLATION

(1) Position the filter-drier and its bracket to the
front fender wheelhouse front extension as a unit
and loosely secure it with the mounting screw.

(2) Remove the tape or plugs from the front liquid
line block fitting and the filter-drier inlet. Install the
front liquid line block fitting to the filter-drier inlet
and secure the connection with a screw. Tighten the
mounting screw to 13.5 N·m (120 in. lbs.).

(3) Remove the tape or plugs from the rear liquid
line block fitting and the filter-drier outlet. Install
the rear liquid line block fitting to the filter-drier

outlet and secure the connection with a screw.
Tighten the mounting screw to 13.5 N·m (120 in.
lbs.).

(4) Tighten the filter-drier bracket mounting screw

to 6.8 N·m (60 in. lbs.).

(5) Connect the battery negative cable.

(6) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(7) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

NOTE: If the filter-drier is replaced, add 30 millili­ters (1 fluid ounce) of refrigerant oil to the refriger­ant system. Use only refrigerant oil of the type
recommended for the compressor in the vehicle.

CONDENSER

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

CAUTION: Before removing the condenser, note the
location of each of the radiator and condenser air
seals. These seals are used to direct air through the
condenser and radiator. The air seals must be rein­stalled in their proper locations in order for the air
conditioning and engine cooling systems to per­form as designed.

DN HEATING AND AIR CONDITIONING 24 - 41

REMOVAL AND INSTALLATION (Continued)

REMOVAL

(1)

Disconnect and isolate the battery negative cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3)

Disconnect the refrigerant line fitting that secures
the discharge line to the condenser inlet. See Refrigerant
Line Coupler in the Removal and Installation section of
this group for the procedures. Install plugs in, or tape
over all of the opened refrigerant line fittings.

(4) Disconnect the refrigerant line fitting that
secures the liquid line to the condenser outlet. See
Refrigerant Line Coupler in the Removal and Instal­lation section of this group for the procedures. Install
plugs in, or tape over all of the opened refrigerant
line fittings.

(5) Remove the two screws that secure the radiator
and fan shroud module to the inside of the upper
radiator crossmember.

(6) On models equipped with a V-8 engine, remove
the radiator from the engine compartment. Refer to
Group 7 - Cooling Systems for the procedures.

(7) Remove the two screws that secure the con­denser to the outside of the upper radiator cross­member (Fig. 33).

INSTALLATION

(1) With the radiator and fan shroud module tilted
towards the engine, carefully position the lower con­denser mounts in the lower crossmember isolators.

(2) Reinstall the two screws that secure the con­denser to the outside of the upper radiator cross­member and tighten to 10.7 N·m (95 in. lbs.).

(3) On models equipped with a V-8 engine, rein­stall the radiator to the engine compartment. Refer
to Group 7 - Cooling Systems for the procedures.

(4) Reinstall the two screws that secure the radia­tor and fan shroud module to the inside of the upper
radiator crossmember.

(5) Remove the plugs or tape from the refrigerant
line fittings on the liquid line and the condenser out­let. Connect the liquid line to the condenser outlet.
See Refrigerant Line Coupler in the Removal and
Installation section of this group for the procedures.

Remove the plugs or tape from the refrigerant

(6)
line fittings on the discharge line and the condenser
inlet. Connect the discharge line to the condenser inlet.
See Refrigerant Line Coupler in the Removal and
Installation section of this group for the procedures.

(7) Check that all of the condenser and radiator
air seals are in their proper locations.

(8) Connect the battery negative cable.

(9) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(10) Charge the refrigerant system. See Refriger­ant System Charge in the Service Procedures section
of this group.

NOTE: If the condenser is replaced, add 30 millili­ters (1 fluid ounce) of refrigerant oil to the refriger­ant system. Use only refrigerant oil of the type
recommended for the compressor in the vehicle.

Fig. 33 Condenser Remove/Install

(8) Tilt the top of the radiator and fan shroud
module towards the engine, using care not to damage
the radiator fins on the engine cooling fan.

(9) With the radiator and fan shroud module
tilted, carefully lift the condenser upwards until the
lower condenser mounts are clear of the isolators in
the lower crossmember.

(10) Remove the condenser from the vehicle.

UNDERBODY REFRIGERANT LINE

The underbody refrigerant lines are used only on
models with the optional rear overhead A/C unit.
Both the underbody suction line and the underbody
liquid line are available for separate service replace­ment, and may be removed from the vehicle indepen­dently for service.

Any kinks or sharp bends in the refrigerant plumbing
will reduce the capacity of the entire air conditioning
system. Kinks and sharp bends reduce the flow of
refrigerant in the system. High pressures are produced
in the refrigerant system when the air conditioning
compressor is operating. Extreme care must be exer­cised to make sure that each of the refrigerant system
connections is pressure-tight and leak free.

24 - 42 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1)

Disconnect and isolate the battery negative cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) From the engine compartment, disconnect the
underbody liquid line refrigerant line coupler at the
liquid line extension and the underbody suction line
refrigerant line coupler at the suction line jumper
(Fig. 34). See Refrigerant Line Coupler in the
Removal and Installation section of this group for the
procedures. Install plugs in, or tape over all of the
opened refrigerant line fittings.

(4) Raise and support the vehicle.

From under the vehicle, disconnect the underbody

(5)
liquid line refrigerant line coupler at the B-pillar liquid
line and the underbody suction line refrigerant line cou­pler at the B-pillar suction line. See Refrigerant Line
Coupler in the Removal and Installation section of this
group for the procedures. Install plugs in, or tape over
all of the opened refrigerant line fittings.

(6) Remove the screws that secure the three
underbody refrigerant line clamps to the underbody.

(7) Remove the underbody refrigerant line unit
from the vehicle.

INSTALLATION

(1) From under the vehicle, position the underbody
refrigerant line unit to the underbody and secure the
refrigerant line clamps with the mounting screws in
three places. Tighten the mounting screws to 2.2 N·m
(20 in. lbs.).

(2) Remove the tape or plugs from the refrigerant
line fittings at the rear of the underbody liquid and
suction lines and at the B-pillar liquid and suction
lines. Connect the underbody refrigerant lines to the
B-pillar refrigerant lines. See Refrigerant Line Cou­pler in the Removal and Installation section of this
group for the procedures.

(3) Lower the vehicle.

(4) From the engine compartment, remove the tape
or plugs from the refrigerant line fittings at the front
of the underbody liquid and suction lines and at the
liquid line extension and the suction line jumper.
Connect the underbody refrigerant lines to the
engine compartment refrigerant lines. See Refriger­ant Line Coupler in the Removal and Installation
section of this group for the procedures.

(5) Connect the battery negative cable.

(6) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(7) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

Fig. 34 Underbody Refrigerant Line Remove/Install

DN HEATING AND AIR CONDITIONING 24 - 43

REMOVAL AND INSTALLATION (Continued)

B-PILLAR REFRIGERANT LINE

The B-pillar refrigerant lines are used only on
models with the optional rear overhead A/C unit.
Both the B-pillar suction line and the B-pillar liquid
line are available for separate service replacement.
Each line may be removed independently from the
vehicle for service.

Any kinks or sharp bends in the refrigerant plumb­ing will reduce the capacity of the entire air condi­tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. High pressures are
produced in the refrigerant system when the air con­ditioning compressor is operating. Extreme care must
be exercised to make sure that each of the refriger­ant system connections is pressure-tight and leak
free.

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) Raise and support the vehicle.

(4) From under the vehicle, disconnect the under­body liquid line refrigerant line coupler at the B-pil­lar liquid line and the underbody suction line

refrigerant line coupler at the B-pillar suction line.
See Refrigerant Line Coupler in the Removal and
Installation section of this group for the procedures.
Install plugs in, or tape over all of the opened refrig­erant line fittings.

(5) Lower the vehicle.

(6) Remove the headliner from the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures. The B-pillar upper and lower trim
must be removed.

(7) From the passenger compartment, remove the
fasteners that secure the block fittings at the top of
the B-pillar refrigerant lines to the rear overhead
A/C unit (nut from stud - liquid line) (nut and bolt ­suction line), and disengage the fittings (Fig. 35).
Install plugs in, or tape over all of the opened refrig­erant line fittings.

(8) Remove the two screws that secure the B-pillar
refrigerant line clamps to the B-pillar (Fig. 36).

(9) Remove the two screws that secure the B-pillar
refrigerant line clamp and seal unit to the floor panel
at the base of the B-pillar.

(10) Tilt the top of the B-pillar refrigerant line
unit towards the front of the vehicle far enough so

Fig. 35 Rear Overhead A/C Unit Refrigerant Line

Remove/Install

Fig. 36 B-Pillar Refrigerant Lines Remove/Install

that the lower end of the unit can be lifted out
through the hole in the floor panel.

(11) Remove the B-pillar refrigerant line unit from

the passenger compartment.

24 - 44 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

NOTE: If either the liquid line or the suction line is
removed from the B-pillar refrigerant line clamp and
seal, the clamp and seal will be damaged. Replace
the clamp and seal with a new unit.

INSTALLATION

(1) Position the B-pillar refrigerant line unit in the
passenger compartment with the lower end of the
lines inserted through the hole in the floor panel at
the base of the B-pillar, and the top end of the lines
oriented towards the front of the vehicle.

(2) Tilt the top of the B-pillar refrigerant line unit
up into position near the rear overhead A/C unit.

(3) Remove the tape or plugs from block fittings at
the top of the B-pillar refrigerant line unit, and from
the fittings on the rear overhead A/C unit. Install the
B-pillar refrigerant line block fittings over the one
stud on the rear overhead A/C unit. Install the bolt
holding the suction line, and secure the connections
with the mounting nuts. Tighten the mounting nuts
to 11.3 N·m (100 in. lbs.).

(4) Position the B-pillar refrigerant line clamp and
seal over the hole in the floor panel and secure it
with two screws. Tighten the mounting screws to 2.2
N·m (20 in. lbs.).

(5) Position the two B-pillar refrigerant line
clamps over the mounting holes in the inner B-pillar

and secure each clamp with a screw. Tighten the
mounting screws to 2.2 N·m (20 in. lbs.).

(6) Reinstall the headliner in the passenger com­partment. Refer to Group 23 - Body for the proce­dures. Reinstall the lower B-pillar trim panel, upper
trim panel, and seat belt bolt adjuster.

(7) Raise and support the vehicle.

(8) From under the vehicle, remove the tape or
plugs from the refrigerant line fittings at the under­body and B-pillar liquid lines, and from the under­body and B-pillar suction lines. Connect the
underbody refrigerant lines to the B-pillar refriger­ant lines. See Refrigerant Line Coupler in the
Removal and Installation section of this group for the
procedures.

(9) Connect the battery negative cable.

(10) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(11) Charge the refrigerant system. See Refriger­ant System Charge in the Service Procedures section
of this group.

VACUUM CHECK VALVE

(1) Unplug the vacuum supply line connector at
the vacuum check valve (Fig. 37).

(2) Note the orientation of the check valve in the
vacuum supply line for correct reinstallation.

Fig. 37 Vacuum Supply

DN HEATING AND AIR CONDITIONING 24 - 45

REMOVAL AND INSTALLATION (Continued)

(3) Unplug the vacuum check valve from the vac-

uum supply line fittings.

(4) Reverse the removal procedures to install.

VACUUM RESERVOIR

(1) Disconnect and isolate the battery negative

cable.

(2) Remove the wiper arms from the wiper pivots.
Refer to Wiper Arm in the Removal and Installation
section of Group 8K - Wiper and Washer Systems for
the procedures.

(3) Remove the weatherstrip along the front edge
of the cowl plenum cover/grille panel and the cowl
plenum panel (Fig. 38).

Fig. 38 Cowl Plenum Cover/Grille Panel

Weatherstrip

(4) Remove the four plastic nuts that secure the
cowl plenum cover/grille panel to the studs on the
cowl top panel near the base of the windshield (Fig.

39).

(5) Remove the one plastic rivet that secures the
front corner on each side of the cowl plenum cover/
grille panel to the cowl plenum panel.

(6) Remove the one plastic push-in retainer that
secures the rear corner on each side of the cowl ple­num cover/grille panel to the windshield reveal mold­ing.

(7) Unsnap the slotted center hole on each side of
the cowl plenum cover/grille panel from the adhesive­backed snap fastener. (If equipped: This feature

may not be on all models).

(8) Lift the cowl plenum cover/grille panel from the
cowl top far enough to access the windshield washer
nozzle and vacuum plumbing near the right end of
the cowl plenum.

(9) Disconnect the windshield washer supply hose
at the in-line connector.

(10) Disconnect the vacuum supply hose from the
vacuum reservoir, which is secured to the underside
of the right end of the cowl plenum cover/grille panel
(Fig. 40).

(11) Remove the cowl plenum cover/grille panel
from the vehicle.

Fig. 39 Cowl Plenum Cover/Grille Panel Remove/Install

24 - 46 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

Fig. 40 Vacuum Reservoir

(12) Remove the three screws that secure the vac­uum reservoir to the underside of the cowl plenum
cover/grille panel.

(13) Remove the vacuum reservoir from the cowl
plenum cover/grille panel.

(14) Reverse the removal procedures to install.
Tighten the vacuum reservoir mounting screws to 2.2
N·m (20 in. lbs.).

Fig. 41 Heater-A/C Control Remove/Install

HEATER-A/C CONTROL

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR

INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Remove the cluster bezel from the instrument
panel. Refer to Cluster Bezel in the Removal and
Installation section of Group 8E - Instrument Panel
Systems for the procedures.

(3) Remove the four screws that secure the heater­A/C control to the instrument panel (Fig. 41).

(4) Pull the heater-A/C control assembly away
from the instrument panel far enough to access the
connections on the back of the control.

(5) Unplug the wire harness connector from the
back of the heater-A/C control (Fig. 42).

(6) Disconnect the wire harness retainer from the
side of the heater-A/C control assembly.

Fig. 42 Heater-A/C Control Connections

(7) Remove the two stamped nuts that secure the
vacuum harness connector and unplug the connector
from the back of the heater-A/C control.

(8) Release the temperature control cable housing
flag retainer latch in the receptacle on the back of
the heater-A/C control and disengage the flag
retainer from the receptacle.

(9) Rotate the heater-A/C control assembly to align
the cable core with the slot on the end of the temper­ature control lever and disengage the cable end from
the lever.

(10) Remove the heater-A/C control from the
instrument panel.

DN HEATING AND AIR CONDITIONING 24 - 47

REMOVAL AND INSTALLATION (Continued)

INSTALLATION

(1) Connect the temperature control cable core end
to the temperature control lever on the back of the
heater-A/C control.

(2) Connect the temperature control cable housing
flag retainer to the receptacle on the back of the
heater-A/C control.

(3) Plug in the vacuum harness connector and
install the two stamped nuts to secure the connector
to the back of the heater-A/C control.

(4) Plug the wire harness connector into the back
of the heater-A/C control.

(5) Reinstall the wire harness retainer to the side
of the heater-A/C control.

(6) Position the heater-A/C control in the instru­ment panel and secure it with four screws. Tighten
the screws to 2.2 N·m (20 in. lbs.).

(7) Reinstall the cluster bezel to the instrument
panel. Refer to Cluster Bezel in the Removal and
Installation section of Group 8E - Instrument Panel
Systems for the procedures.

(8) Connect the battery negative cable.

(9) Adjust the temperature control cable. See Tem­perature Control Cable in the Adjustments section of
this group for the procedures.

(3) Pull the rear blower motor switch away from
the headliner far enough to access and unplug the
wire harness connector from the back of the switch.

(4) Remove the rear blower motor switch from the
headliner.

INSTALLATION

(1) Plug the wire harness connector into the back
of the rear blower motor switch.

(2) Tuck the wire harness back through the rear
blower motor switch mounting hole in the headliner.

(3) Gently press the rear blower motor switch into
the mounting hole in the headliner until it snaps into
place.

(4) Connect the battery negative cable.

BLOWER MOTOR RELAY

(1) Disconnect and isolate the battery negative
cable.

(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 44).

REAR BLOWER MOTOR SWITCH

The rear blower motor switch is used only on mod­els with the optional rear overhead air conditioning
unit.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Using a trim stick or another suitable wide
flat-bladed tool, gently pry above the two indenta­tions at the outer perimeter of the rear blower motor
switch to release it from the headliner (Fig. 43).

Fig. 43 Rear Blower Motor Switch Remove/Install

Fig. 44 Power Distribution Center

(3) Refer to the label on the PDC for blower motor

relay identification and location.

(4) Unplug the blower motor relay from the PDC.

(5) Install the blower motor relay by aligning the
relay terminals with the cavities in the PDC and
pushing the relay firmly into place.

(6) Install the PDC cover.

(7) Connect the battery negative cable.

(8) Test the relay operation.

HIGH SPEED BLOWER MOTOR RELAY

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

24 - 48 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

(1) Disconnect and isolate the battery negative

cable.

(2) Remove the steering column opening cover and
knee blocker from the instrument panel. Refer to
Steering Column Opening Cover and Knee Blocker in
the Removal and Installation section of Group 8E ­Instrument Panel Systems for the procedures.

(3) Reach through the outboard side of the steer­ing column opening in the instrument panel to access
the relay and fuse block on the back of the junction
block (Fig. 45).

Fig. 45 Relay and Fuse Block

(4) Unplug the high speed blower motor relay from

the relay and fuse block.

(5) Install the high speed blower motor relay by
aligning the relay terminals with the cavities in the
relay and fuse block and pushing the relay firmly
into place.

(6) Connect the battery negative cable.

(7) Test the relay operation.

(8) Reverse the remaining removal procedures to
complete the installation.

BLOWER MOTOR RESISTOR

FRONT

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Remove the cowl plenum cover/grille panel
from the cowl top. See Vacuum Reservoir in the
Removal and Installation section of this group for the
procedures.

(3) Reach through the cowl plenum access hole
(Fig. 46) to remove the two hex screws that secure
the front blower motor resistor to the cowl plenum
panel.

Fig. 46 Blower Motor Resistor Remove/Install

(4) Pull the front blower motor resistor and its
wire harness out of the plenum panel and through
the cowl plenum access hole far enough to access the
wire harness connector.

(5) Unplug the front blower motor resistor from
the wire harness connector.

(6) Remove the front blower motor resistor from
the cowl plenum.

INSTALLATION

(1) Plug the front blower motor resistor into the
wire harness connector.

(2) Install the front blower motor resistor to the
cowl plenum panel by feeding the resistor and wire
harness back through the cowl plenum access hole.

(3) Install and tighten the two screws that secure
the front blower motor resistor to the cowl plenum
panel. Tighten the mounting screws to 2.2 N·m (20
in. lbs.).

(4) Reinstall the cowl plenum cover/grille panel to
the cowl top. See Vacuum Reservoir in the Removal
and Installation section of this group for the proce­dures.

(5) Connect the battery negative cable.

DN HEATING AND AIR CONDITIONING 24 - 49

REMOVAL AND INSTALLATION (Continued)

REAR

The rear blower motor resistor is used only on

models with the optional rear overhead A/C unit.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Remove the headliner from the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(3) Disconnect the B-pillar drain hoses from the
wye fittings on each side of the rear overhead A/C
unit (Fig. 47).

(6) Feed the rear blower motor switch wire har­ness and connector through the hole in the right end
of the rear overhead A/C unit lower housing cover
while removing the cover from the unit.

(7) Disengage the rear blower motor resistor wire
harness connector retainer from the mounting hole in
the right rear corner of the rear overhead A/C unit
upper housing cover(Fig. 49).

Fig. 47 Rear Overhead A/C Drain Hose Remove/

Install

(4) Remove the nine screws that secure the lower

housing cover to the rear overhead A/C unit.

(5) Release the lower housing cover snap retainer
near the center of the outlet side (rear) of the rear
overhead A/C unit (Fig. 48).

Fig. 48 Rear Overhead A/C Unit Lower Housing

Cover Remove/Install

Fig. 49 Rear Blower Motor Resistor Remove/Install

(8) Unplug the rear blower motor resistor wire

harness connector.

(9) Remove the screw that secures the rear blower
motor resistor bracket to the rear overhead A/C unit
upper housing cover.

(10) Remove the rear blower motor resistor and
bracket as a unit from the rear overhead A/C unit.

INSTALLATION

(1) Position the rear blower motor resistor and
bracket in the right rear corner of the rear overhead
A/C unit upper housing cover and secure it with the
mounting screw. Tighten the mounting screw to 2.2
N·m (20 in. lbs.).

(2) Plug in the rear blower motor resistor wire
harness connector.

(3) Engage the rear blower motor resistor wire
harness connector retainer to the mounting hole in
the right rear corner of the rear overhead A/C unit
upper housing cover.

(4) Feed the rear blower motor switch wire har­ness and connector through the hole in the right end
of the rear overhead A/C unit lower housing cover
while positioning the cover to the unit.

(5) Be certain that the lower housing cover snap
retainer near the center of the outlet side (rear) of
the rear overhead A/C unit is engaged.

(6) Install the nine screws that secure the lower
housing cover to the rear overhead A/C unit. Tighten
the mounting screws to 2.2 N·m (20 in. lbs.).

24 - 50 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

(7) Connect the B-pillar drain hoses to the wye fit-

tings on each side of the rear overhead A/C unit.

(8) Reinstall the headliner to the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(9) Connect the battery negative cable.

TEMPERATURE CONTROL CABLE

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Roll down the instrument panel assembly, but
do not remove it from the vehicle. Refer to Instru­ment Panel Assembly in the Removal and Installa­tion section of Group 8E - Instrument Panel Systems
for the procedures.

(3) Disconnect the temperature control cable from
the heater-A/C control. See Heater-A/C Control in the
Removal and Installation section of this group for the
procedures.

(4) Disconnect the temperature control cable hous-

ing flag retainer from the receptacle on the top of the
heater-A/C housing (Fig. 50).

(5) Pull the temperature control cable core self-ad­juster clip off of the pin on the end of the blend-air
door lever.

(6) Remove the temperature control cable from the
vehicle.

Fig. 50 Temperature Control Cable Remove/Install

INSTALLATION

Before installing the temperature control cable, be
certain that the self-adjuster clip is properly posi­tioned (Fig. 51). This measurement must be made
with the cable end bottomed against the flag retainer
on the heater-A/C control end of the cable housing.
The measurement is taken from the end of the flag
retainer on the heater-A/C housing end of the cable
to the center of the self-adjuster clip. If the self-ad­juster clip is not properly positioned, slide the clip up
or down the cable core as required to achieve the
specified dimension.

(1) Connect the temperature control cable to the
heater-A/C control. See Heater-A/C Control in the
Removal and Installation section of this group for the
procedures.

(2) Route the cable through the instrument panel.
Position the cable end near the connection points on
the HVAC unit assembly, making sure not to kink or
distort the cable.

Fig. 51 Temperature Control Cable Self-Adjuster Clip

DN HEATING AND AIR CONDITIONING 24 - 51

REMOVAL AND INSTALLATION (Continued)

(3) Push the temperature control cable core self­adjuster clip onto the pin on the end of the blend-air
door lever.

(4) Snap the temperature control cable housing
flag retainer into the receiver on the top of the heat­er-A/C housing.

(5) Reinstall the instrument panel assembly. Refer
to Instrument Panel Assembly in the Removal and
Installation section of Group 8E - Instrument Panel
Systems for the procedures.

(6) Connect the battery negative cable.

(7) Adjust the temperature control cable. See Tem­perature Control Cable in the Adjustments section of
this group for the procedures.

MODE DOOR VACUUM ACTUATOR

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

Fig. 52 Floor-Defrost Door Actuator Remove/Install

(3) Unplug the vacuum harness connector from the

panel-defrost door actuator (Fig. 53).

FLOOR-DEFROST DOOR ACTUATOR

(1) Disconnect and isolate the battery negative
cable.

(2) Remove the instrument panel assembly from
the vehicle. Refer to Instrument Panel Assembly in

the Removal and Installation section of Group 8E ­Instrument Panel Systems for the procedures.

(3) Unplug the two vacuum harness connectors
from the floor-defrost door actuator (Fig. 52).

(4) Remove the push nut retainer that secures the
floor-defrost door actuator link to the floor-defrost
door crank arm.

(5) Remove the two screws that secure the floor­defrost door actuator to the heater-A/C housing.

(6) Disengage the floor-defrost door actuator link
from the floor-defrost door crank arm and remove the
actuator from the heater-A/C housing.

(7) Reverse the removal procedures to install.
Tighten the floor-defrost door actuator mounting
screws to 2.2 N·m (20 in. lbs.).

PANEL-DEFROST DOOR ACTUATOR

(1) Disconnect and isolate the battery negative
cable.

(2) Remove the instrument panel assembly from
the vehicle. Refer to Instrument Panel Assembly in
the Removal and Installation section of Group 8E ­Instrument Panel Systems for the procedures.

Fig. 53 Panel-Defrost Door Actuator

(4) Remove the two screws that secure the panel-

defrost door actuator to the heater-A/C housing.

(5) Rotate the panel-defrost door actuator clock­wise about one-quarter turn to disengage the hooked
end of the actuator link from the hole on the end of
the panel-defrost door lever.

(6) Remove the panel-defrost door actuator from
the heater-A/C housing.

24 - 52 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

(7) Reverse the removal procedures to install.
Tighten the panel-defrost door actuator mounting
screws to 2.2 N·m (20 in. lbs.).

RECIRCULATION AIR DOOR ACTUATOR

A recirculation air door and vacuum actuator are
used only on models with the optional air condition­ing system.

(1) Disconnect and isolate the battery negative
cable.

(2) Remove the instrument panel assembly from
the vehicle. Refer to Instrument Panel Assembly in
the Removal and Installation section of Group 8E ­Instrument Panel Systems for the procedures.

(3) If the vehicle is so equipped, and the heater­A/C housing is in its installed position in the vehicle,
remove the Infinity speaker system amplifier. Refer
to Amplifier in the Removal and Installation section
of Group 8F - Audio Systems for the procedures.

(4) Unplug the two vacuum harness connectors
from the recirculation air door actuator (Fig. 54).

(8) Reverse the removal procedures to install.
Tighten the mounting nuts until the recirculation air
door actuator is seated to the blower motor housing
cover.

HEATER-A/C HOUSING

The heater-A/C housing assembly must be removed
from the vehicle and disassembled for service access
of the blower motor, blower motor wheel, heater core,
evaporator coil, blend-air door, and each of the vari­ous mode control doors.

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

Fig. 54 Recirculation Air Door Actuator Remove/

Install

(5) Remove the two stamped nuts that secure the
recirculation air door actuator to the blower motor
housing cover.

(6) Unhook the actuator link from the recirculation
air door lever.

(7) Remove the actuator from the blower motor
housing cover.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Remove the instrument panel from the vehicle.
Refer to Instrument Panel Assembly in the Removal
and Installation section of Group 8E - Instrument
Panel Systems for the procedures.

(3) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(4) Remove the front expansion valve from the
evaporator tube mounting flange. See Expansion
Valve in the Removal and Installation section of this
group for the procedures. Install plugs in, or tape
over all of the opened refrigerant line fittings.

(5) Drain the engine cooling system. Refer to
Group 7 - Cooling System for the procedures.

(6) Disconnect the heater hoses from the heater
core tubes. Refer to Group 7 - Cooling System for the
procedures. Install plugs in, or tape over the opened
heater core tubes.

(7) Remove the four nuts from the heater-A/C
housing mounting studs on the engine compartment
side of the dash panel (Fig. 55).

(8) Disengage the front floor panel transmission
tunnel duct from the adapter on the heater-A/C hous­ing.

DN HEATING AND AIR CONDITIONING 24 - 53

REMOVAL AND INSTALLATION (Continued)

Fig. 55 Heater-A/C Housing Remove/Install

(9) Remove the nut that secures the heater-A/C
housing mounting brace to the stud on the passenger
compartment side of the dash panel.

(10) Pull the heater-A/C housing rearward far
enough for the mounting studs and the evaporator
condensate drain tube to clear the dash panel holes.

(11) Remove the heater-A/C housing from the vehi­cle.

DISASSEMBLY

(1) Place the heater-A/C housing on a work bench,
with the heater-A/C housing cover facing down.

(2) Remove the two screws that secure the heater­A/C housing cover to the top of the blower motor
housing cover.

(3) If the vehicle is so equipped, unplug the two
vacuum harness connectors from the recirculation air
door actuator.

(4) Unplug the vacuum harness connector from the
panel-defrost door actuator.

(5) Remove the four screws that secure the floor
duct to the bottom of the heater-A/C housing and
remove the duct from the housing.

(6) Remove the two screws that secure the heater­A/C housing cover to the lower housing near the floor
outlet (Fig. 56).

(7) Turn the heater-A/C housing over on the work
bench, with the heater-A/C housing cover facing up.

Fig. 56 Heater-A/C Housing Floor Outlet Screws

(8) Disengage the vacuum harness retainer from
the hole near the left end of the heater-A/C housing
cover.

(9) Remove the vacuum harness from the molded
clips on the heater-A/C housing cover (Fig. 57).

24 - 54 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

Fig. 58 Panel-Defrost Door Lever Remove

Fig. 57 Blend-Air Door Lever Remove/Install

(10) Remove the thirteen screws that secure the
perimeter of the housing cover to the heater-A/C
housing.

(11) Remove the nut that secures the blend-air
door lever to the blend-air door pivot shaft and
remove the lever.

(12) Gently pry off the push nut that secures the
heater-A/C housing cover to the heater-A/C housing
post.

(13) Using a trim stick or another suitable wide
flat-bladed tool, gently pry the panel-defrost door
lever off of the panel-defrost door pivot shaft (Fig.

58).

(14) Pull up the perimeter edges of the heater-A/C
housing cover far enough to separate the cover seal­ant from the heater-A/C housing.

(15) Remove the housing cover from the heater­A/C housing.

(16) If the vehicle is so equipped, remove the recir­culation air door actuator from the blower motor
housing cover. See Mode Door Vacuum Actuators in
the Removal and Installation section of this group for
the procedures.

(17) Remove the six screws that secure the blower
motor housing cover to the heater-A/C housing (Fig.

59).

(18) Remove the blower motor housing cover from
the heater-A/C housing.

ASSEMBLY

(1) Before installing the blower motor housing
cover, be certain that the cover sealant is in place
and in good condition (Fig. 60).

Fig. 59 Blower Motor Housing Cover Remove/Install

(2) Position the blower motor housing cover to the

heater-A/C housing.

(3) Install the six screws that secure the blower
motor housing cover to the heater-A/C housing.
Tighten the screws to 2.2 N·m (20 in. lbs.).

(4) If the vehicle is so equipped, reinstall the recir­culation air door actuator. See Mode Door Vacuum
Actuators in the Removal and Installation section of
this group for the procedures.

(5) Before installing the heater-A/C housing cover,
be certain that the cover sealant is in place and in
good condition (Fig. 61).

(6) Position the heater-A/C housing cover on the
heater-A/C housing. Be certain that the pivots for the
floor-defrost, the panel-defrost, the blend-air, and the
recirculation air (if the vehicle is so equipped) doors
are properly positioned.

DN HEATING AND AIR CONDITIONING 24 - 55

REMOVAL AND INSTALLATION (Continued)

(15) Position the floor duct to the bottom of the
heater-A/C housing and secure with four screws.
Tighten the screws to 2.2 N·m (20 in. lbs.).

(16) Plug in the vacuum harness connector to the
panel-defrost door actuator.

(17) If the vehicle is so equipped, plug in the two
vacuum harness connectors to the recirculation air
door actuator.

(18) Install the two screws that secure the heater­A/C housing cover to the top of the blower motor
housing cover. Tighten the screws to 2.2 N·m (20 in.
lbs.).

(19) Reinstall the heater-A/C housing in the vehi­cle.

INSTALLATION

(1) Position the heater-A/C housing to the dash
panel. Be certain that the evaporator condensate
drain tube and the housing mounting studs are
inserted into their correct mounting holes.

(2) Install the nut that secures the heater-A/C
housing mounting brace to the stud on the passenger

Fig. 60 Blower Motor Housing Cover Sealant

Fig. 61 Heater-A/C Housing Cover Sealant

(7) Reinstall the push nut that secures the heater-

A/C housing cover to the heater-A/C housing post.

(8) Install the thirteen screws that secure the
perimeter of the housing cover to the heater-A/C
housing. Tighten the screws to 2.2 N·m (20 in. lbs.).

(9) Snap the panel-defrost door lever onto the pan­el-defrost door pivot shaft.

(10) Install the blend-air door lever to the blend­air door pivot shaft and secure it to the shaft with
the nut.

(11) Install the vacuum harness retainer into the
hole near the left end of the heater-A/C housing
cover.

(12) Route the vacuum harness through the
molded clips on the heater-A/C housing cover.

(13) Turn the heater-A/C housing over on the work
bench, with the heater-A/C housing cover facing
down.

(14) Install the two screws that secure the heater­A/C housing cover to the lower housing near the floor
outlet. Tighten the screws to 2.2 N·m (20 in. lbs.).

compartment side of the dash panel. Tighten the nut
to 11 N·m (95 in. lbs.).

(3) Engage the front floor panel transmission tun-

nel duct with the adapter on the heater-A/C housing.

(4) Install and tighten the four nuts onto the heat­er-A/C housing mounting studs on the engine com­partment side of the dash panel. Tighten the nuts to
7 N·m (60 in. lbs.).

(5) Unplug or remove the tape from the heater
core tubes. Connect the heater hoses to the heater
core tubes and fill the engine cooling system. Refer to
Group 7 - Cooling System for the procedures.

(6) Reinstall the front expansion valve to the evap­orator tube mounting flange. See Expansion Valve in
the Removal and Installation section of this group for
the procedures.

(7) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(8) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

(9) Reinstall the instrument panel in the vehicle.
Refer to Instrument Panel Assembly in the Removal
and Installation section of Group 8E - Instrument
Panel Systems for the procedures.

(10) Connect the battery negative cable.

(11) Start the engine and check for proper opera­tion of the heating and air conditioning systems.

24 - 56 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

REAR OVERHEAD A/C UNIT

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) Remove the headliner from the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(4) From the passenger compartment, remove the
nut from the bolt, (suction line) and nut from stud,
(liquid line) that secure the block fittings at the top
of the B-pillar refrigerant lines on the rear overhead
A/C unit, and disengage the fittings (Fig. 62). Install
plugs in, or tape over all of the opened refrigerant
line fittings.

Fig. 63 Rear Overhead A/C Drain Hose Remove/

Install

Fig. 62 Rear Overhead A/C Unit Refrigerant Line

Remove/Install

(5) Disconnect the B-pillar drain hoses from the
wye fittings on each side of the rear overhead A/C
unit (Fig. 63).

(6) Unplug the rear overhead A/C unit wire har­ness connector located at the left side of the unit.

(7) Loosen but do not remove the two screws that
secure the mounting bracket on the left end of the
rear overhead A/C unit to the left roof rail (Fig. 64).

Fig. 64 Rear Overhead A/C Unit Remove/Install

(8) Support the right end of the rear overhead A/C
unit while removing the two screws that secure the
mounting bracket on the right end of the unit to the
right roof rail.

(9) Slide the rear overhead A/C unit towards the
right side of the vehicle far enough to disengage the
slotted holes on the left end of the mounting bracket
from the loosened screws in the left roof rail.

(10) Remove the rear overhead A/C unit from the
passenger compartment.

INSTALLATION

(1) Engage the slotted holes in the left end of rear
overhead A/C unit mounting bracket with the loos­ened screws in the left roof rail.

DN HEATING AND AIR CONDITIONING 24 - 57

REMOVAL AND INSTALLATION (Continued)

(2) Support the right end of the rear overhead A/C
unit while installing the two screws that secure the
mounting bracket on the right end of the unit to the
right roof rail. Tighten all of the mounting screws to

11.9 N·m (105 in. lbs.).

(3) Plug in the rear overhead A/C unit wire har­ness connector located at the left side of the unit.

(4) Connect the B-pillar drain hoses to the wye fit­tings on each side of the rear overhead A/C unit.

(5) Remove the tape or plugs from block fittings at
the top of the B-pillar refrigerant line unit, and from
the fittings on the rear overhead A/C unit. Install the
B-pillar refrigerant line block fittings over the one
stud on the rear overhead A/C unit. Install the bolt
holding the suction line, and secure the connections
with the mounting nuts. Tighten the mounting nuts
to 11.3 N·m (100 in. lbs.).

(6) Reinstall the headliner in the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(7) Connect the battery negative cable.

(8) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(9) Charge the refrigerant system. See Refrigerant
System Charge in the Service Procedures section of
this group.

of the passenger compartment side of the heater-A/C
housing while feeding the blower motor wire harness,
grommet and connector through the hole on the dash
panel side of the housing.

remove the wheel from the blower motor shaft (Fig.

66).

Fig. 65 Blower Motor Remove/Install

(3) Pull the blower motor and wheel assembly out

(4) Remove the blower wheel retainer clip and

NOTE: If the rear overhead A/C unit is replaced,
add 30 milliliters (1 fluid ounce) of refrigerant oil to
the refrigerant system. Use only refrigerant oil of
the type recommended for the compressor in the
vehicle.

BLOWER MOTOR

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

FRONT

REMOVAL

(1) Remove and disassemble the heater-A/C hous­ing. See Heater-A/C Housing in the Removal and
Installation section of this group for the procedures.

(2) Remove the three screws that secure the
blower motor, air spoiler, and blower wheel assembly
to the heater-A/C housing (Fig. 65).

Fig. 66 Blower Motor Wheel Remove/Install

INSTALLATION

(1) Press the blower wheel hub onto the blower
motor shaft. Be sure the flat on the blower motor
shaft is indexed to the flat on the inside of the blower
wheel hub.

(2) Install the retainer clip over the blower wheel
hub. The ears of the retainer clip must be indexed
over the flats on the blower motor shaft and blower
wheel hub.

(3) Place the blower motor, air spoiler, and wheel
assembly inside the heater-A/C housing and feed the
blower motor wire harness connector through the
grommet hole in the dash panel side of the housing.

24 - 58 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

(4) Pull the blower motor wiring through the hole
from the dash panel side of the heater-A/C housing
until the grommet is seated, while positioning the
blower motor and blower wheel assembly inside the
housing.

(5) Install the three screws that secure the blower
motor, air spoiler, and wheel assembly to the heater­A/C housing. Tighten the screws to 2.2 N·m (20 in.
lbs.).

(6) Assemble and install the heater-A/C housing.
See Heater-A/C Housing in the Removal and Instal­lation section of this group for the procedures.

REAR

The rear blower motor is used only on models with
the optional rear overhead A/C unit. Because the rear
blower motor and wheel are factory balanced units,
the rear blower motor, wheel, housing and mounting
hardware are serviced only as a complete unit.

REMOVAL

(1) Disconnect and isolate the battery negative
cable.

(2) Remove the headliner from the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(3) Disconnect the B-pillar drain hoses from the
wye fittings on each side of the rear overhead A/C
unit (Fig. 67).

Fig. 68 Rear Overhead A/C Unit Lower Housing

Cover Remove/Install

(6) Feed the rear blower motor switch wire har­ness and connector through the hole in the right end
of the rear overhead A/C unit lower housing cover
while removing the cover from the unit.

(7) Disengage the rear blower motor wire harness
connector retainer from the mounting hole in the left
rear corner of the rear overhead A/C unit upper hous­ing cover.

(8) Unplug the rear blower motor wire harness
connector(Fig. 69).

Fig. 67 Rear Overhead A/C Drain Hose Remove/

Install

(4) Remove the nine screws that secure the lower

housing cover to the rear overhead A/C unit.

(5) Release the lower housing cover snap retainer
near the center of the outlet side (rear) of the rear
overhead A/C unit (Fig. 68).

Fig. 69 Rear Blower Motor and Wheel Remove/

Install

(9) Remove the four screws that secure the rear
blower motor, wheel and housing unit to the rear
overhead A/C unit upper housing cover.

(10) Lower the rear blower motor, wheel and hous­ing unit far enough to access and disengage the rear
overhead A/C unit wire harness from each end of the
blower housing.

(11) Remove the rear blower motor, wheel and
housing unit from the rear overhead A/C unit.

INSTALLATION

(1) Position the rear blower motor, wheel and
housing unit to the rear overhead A/C unit, and start
the four mounting screws to hold it in position.

DN HEATING AND AIR CONDITIONING 24 - 59

REMOVAL AND INSTALLATION (Continued)

(2) Engage the rear overhead A/C unit wire har­ness in the routing holes on each end of the blower
housing.

(3) Finish installing the four rear blower motor,
wheel and housing unit mounting screws. Tighten
the mounting screws to 3 N·m (27 in. lbs.).

(4) Plug in the rear blower motor wire harness
connector.

(5) Engage the rear blower motor wire harness
connector retainer in the mounting hole in the left
rear corner of the rear overhead A/C unit upper hous­ing cover.

(6) Feed the rear blower motor switch wire har­ness and connector through the hole in the right end
of the rear overhead A/C unit lower housing cover
while positioning the cover to the unit.

(7) Be certain that the lower housing cover snap
retainer near the center of the outlet side (rear) of
the rear overhead A/C unit is engaged.

(8) Install the nine screws that secure the lower
housing cover to the rear overhead A/C unit. Tighten
the mounting screws to 2.2 N·m (20 in. lbs.).

(9) Connect the B-pillar drain hoses to the wye fit­tings on each side of the rear overhead A/C unit.

(10) Reinstall the headliner to the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(11) Connect the battery negative cable.

floor-defrost door actuator link to the floor-defrost
door crank arm (Fig. 71).

Fig. 70 Blend-Air Door Remove/Install

(2) Remove the push nut retainer that secures the

HEATER-A/C HOUSING DOOR

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE

RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

BLEND-AIR DOOR

(1) Remove the heater-A/C housing from the vehi­cle, and remove the housing cover. See Heater-A/C
Housing in the Removal and Installation section of
this group for the procedures.

(2) Lift the blend-air door pivot shaft out of the
pivot hole in the bottom of the heater-A/C housing
(Fig. 70).

(3) Reverse the removal procedures to install.

FLOOR-DEFROST DOOR

(1) Remove the heater-A/C housing from the vehi­cle, and remove the housing cover. See Heater-A/C
Housing in the Removal and Installation section of
this group for the procedures.

Fig. 71 Floor-Defrost Door Remove/Install

(3) Disengage the floor-defrost door actuator link

from the floor-defrost door crank arm.

(4) Remove the floor-defrost door from the heater-

A/C housing.

(5) Reverse the removal procedures to install.

PANEL-DEFROST DOOR

(1) Remove the heater-A/C housing from the vehi-

cle, and remove the housing cover. See Heater-A/C

24 - 60 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

Housing in the Removal and Installation section of
this group for the procedures.

(2) Lift the panel-defrost door out of the heater­A/C housing. Assure that the chute assembly on
the panel-defrost door is properly positioned .

Fig. 73 Recirculation Air Door Remove/Install

CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

Fig. 72 Panel-Defrost Door Remove/Install

(3) Reverse the removal procedures to install.

RECIRCULATION AIR DOOR

A recirculation air door and vacuum actuator are
used only on models with the optional air condition­ing system.

(1) Remove the heater-A/C housing from the vehi-

cle, and remove the housing cover. See Heater-A/C
Housing in the Removal and Installation section of
this group for the procedures.

(2) Remove the recirculation air door actuator from
the blower motor housing cover. See Mode Door Vac­uum Actuators in the Removal and Installation sec­tion of this group for the procedures.

(3) Lift the lower end of the recirculation air door
up far enough so that the door lever is clear of the
recirculation air intake grille, then twist the door to
remove the door pivots from the pivot holes in the
blower motor housing cover (Fig. 73).

(4) Remove the recirculation air door from the
blower motor housing cover.

(5) Reverse the removal procedures to install.

HEATER CORE

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-

REMOVAL

(1) Remove the heater-A/C housing from the vehi­cle, and remove the housing cover. See Heater-A/C
Housing in the Removal and Installation section of
this group for the procedures.

(2) Lift the heater core out of the heater-A/C hous­ing (Fig. 74).

Fig. 74 Heater Core Remove/Install

INSTALLATION

(1) Insert the heater core into the bottom of the
heater-A/C housing.

(2) Reassemble and reinstall the heater-A/C hous­ing in the vehicle. See Heater-A/C Housing in the
Removal and Installation section of this group for the
procedures.

DN HEATING AND AIR CONDITIONING 24 - 61

REMOVAL AND INSTALLATION (Continued)

EVAPORATOR COIL

WARNING: REVIEW THE WARNINGS AND CAU­TIONS IN THE GENERAL INFORMATION SECTION
NEAR THE FRONT OF THIS GROUP BEFORE PER­FORMING THE FOLLOWING OPERATION.

WARNING: ON VEHICLES EQUIPPED WITH AIR­BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE­CAUTIONS COULD RESULT IN ACCIDENTAL AIR­BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

FRONT

REMOVAL

(1) Remove the heater-A/C housing from the vehi­cle, and remove the housing cover. See Heater-A/C
Housing in the Removal and Installation section of
this group for the procedures.

(2) Lift the front evaporator coil out of the heater­A/C housing (Fig. 75).

NOTE: If the front evaporator coil is replaced, add
60 milliliters (2 fluid ounces) of refrigerant oil to the
refrigerant system. Use only refrigerant oil of the
type recommended for the compressor in the vehi­cle.

REAR

The rear evaporator coil is used only on models

with the optional rear overhead A/C unit.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Recover the refrigerant from the refrigerant
system. See Refrigerant Recovery in the Service Pro­cedures section of this group.

(3) Remove the headliner from the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(4) From the passenger compartment, remove the
nuts that secure the block fittings at the top of the
B-pillar refrigerant lines to the studs on the rear
overhead A/C unit, and disengage the fittings (Fig.

76). Install plugs in, or tape over all of the opened
refrigerant line fittings.

Fig. 75 Evaporator Coil Remove/Install

INSTALLATION

(1) Insert the front evaporator coil into the bottom

of the heater-A/C housing.

(2) Reassemble and reinstall the heater-A/C hous­ing in the vehicle. See Heater-A/C Housing in the
Removal and Installation section of this group for the
procedures.

Fig. 76 Rear Overhead A/C Unit Refrigerant Line

Remove/Install

24 - 62 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

(5) Disconnect the B-pillar drain hoses from the
wye fittings on each side of the rear overhead A/C
unit (Fig. 77).

Fig. 79 Rear A/C Tube Retaining Strap Remove/Install

Fig. 77 Rear Overhead A/C Drain Hose Remove/Install

(6) Remove the nine screws that secure the lower
housing cover to the rear overhead A/C unit.

(7) Release the lower housing cover snap retainer
near the center of the outlet side (rear) of the rear
overhead A/C unit (Fig. 78).

Fig. 78 Rear Overhead A/C Unit Lower Housing

Cover Remove/Install

(8) Feed the rear blower motor switch wire har­ness and connector through the hole in the right end
of the rear overhead A/C unit lower housing cover
while removing the cover from the unit.

Remove the screw that secures the rear overhead

(9)
A/C refrigerant tube and block fitting retaining strap to
the right side of the upper housing cover (Fig. 79).

(10) Remove the two screws that secure the rear
evaporator coil to the rear overhead A/C unit upper
housing cover (Fig. 80).

(11) Remove the rear evaporator coil from the rear
overhead A/C unit.

Fig. 80 Rear Evaporator Coil Remove/Install

INSTALLATION

(1)

Position the rear evaporator coil to the rear over­head A/C unit and secure with two mounting screws.
Tighten the mounting screws to 2.2 N·m (20 in. lbs.).

(2) Install the rear overhead A/C refrigerant tube
and block fitting retaining strap to the right side of
the upper housing cover and secure with a screw.
Tighten the mounting screws to 2.2 N·m (20 in. lbs.).

(3) Feed the rear blower motor switch wire har­ness and connector through the hole in the right end
of the rear overhead A/C unit lower housing cover
while positioning the cover to the unit.

(4) Be certain that the lower housing cover snap
retainer near the center of the outlet side (rear) of
the rear overhead A/C unit is engaged.

(5) Install the nine screws that secure the lower
housing cover to the rear overhead A/C unit. Tighten
the mounting screws to 2.2 N·m (20 in. lbs.).

(6) Connect the B-pillar drain hoses to the wye fit­tings on each side of the rear overhead A/C unit.

(7) Remove the tape or plugs from block fittings at
the top of the B-pillar refrigerant line unit, and from

DN HEATING AND AIR CONDITIONING 24 - 63

REMOVAL AND INSTALLATION (Continued)

the fittings on the rear overhead A/C unit. Install the
B-pillar refrigerant line block fittings over the two
studs on the rear overhead A/C unit and secure the
connections with the mounting nuts. Tighten the
mounting nuts to 11.3 N·m (100 in. lbs.).

(8) Reinstall the headliner in the passenger com­partment of the vehicle. Refer to Group 23 - Body for
the procedures.

(9) Connect the battery negative cable.

(10) Evacuate the refrigerant system. See Refriger­ant System Evacuate in the Service Procedures sec­tion of this group.

(11) Charge the refrigerant system. See Refriger­ant System Charge in the Service Procedures section
of this group.

NOTE: If the rear evaporator coil and expansion
valve unit is replaced, add 30 milliliters (1 fluid
ounce) of refrigerant oil to the refrigerant system.
Use only refrigerant oil of the type recommended
for the compressor in the vehicle.

DUCTS AND OUTLETS

from the pivot pins in the outlet housing of the
instrument panel top cover, the instrument cluster
bezel or the center floor console (Fig. 81).

Fig. 81 Outlet Barrels

(2) To install the outlet barrel, position the barrel
in the outlet housing and press inwards firmly and
evenly until the barrel snaps into place.

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS,
REFER TO GROUP 8M - PASSIVE RESTRAINT SYS­TEMS BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM­PONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.

PANEL AND DEFROSTER DUCTS

The panel and defroster ducts are integral to the
instrument panel assembly. The defroster outlets are
integral to the instrument panel top cover. Refer to
Instrument Panel Assembly in the Removal and
Installation section of Group 8E - Instrument Panel
Systems for the service procedures.

OUTLET BARRELS

In addition to the panel outlet barrels in the
instrument panel, models equipped with the bucket
seat option have two outlet barrels for the rear seat
passengers located near the top of upper rear panel
of the center floor console. The service procedures for
all of these outlet barrels is the same. Models with
the optional rear overhead A/C unit also have four
outlet barrels located in the outlet bezel on the head­liner, but these outlet barrels are only serviced as a
unit with the rear overhead A/C outlet bezel.

(1) Using a trim stick or another suitable wide­bladed flat tool, gently pry at the sides of the outlet
barrels to release the snap-fit pivots on the barrel

FRONT SEAT FLOOR DUCT

(1)

Remove the three screws that secure the floor

duct to the bottom of the heater-A/C housing (Fig. 82).

Fig. 82 Front Seat Floor Duct Remove/Install

(Typical)

(2) Remove the floor duct from the heater-A/C

housing.

(3) Reverse the removal procedures to install.

Tighten the mounting screws to 2.2 N·m (20 in. lbs.).

24 - 64 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

Fig. 83 Rear Seat Floor Duct Control - Split Bench Seat

REAR SEAT FLOOR DUCT CONTROL

SPLIT BENCH SEAT

(1) Remove the three retainers that secure the
HVAC rear bezel to the brackets near the back of the
front seat center section (Fig. 83).

(2) Pull the bezel away from the back of the front
seat far enough to access and disengage the control
cable retainer and cable end from the control.

(3) Reverse the removal procedures to install.

BUCKET SEAT

The rear floor duct control and linkage are only
serviced as a unit with the console duct assembly.

(1) Remove the four screws that secure the console

bin and remove the bin from the floor console (Fig.

84).
(2) Reach through the top of the console to disen-

gage the control rod end from the floor duct damper
door pivot.

(3) Remove the floor console from the vehicle and

disassemble as required to remove the console duct
and control assembly from the console as a unit.
Refer to Group 23 - Body for the procedures.

(4) Reverse the removal procedures to install.

DN HEATING AND AIR CONDITIONING 24 - 65

REMOVAL AND INSTALLATION (Continued)

Fig. 84 Rear Seat Floor Duct Control - Bucket Seat

REAR SEAT FLOOR DUCT

The rear seat floor duct damper door is only ser-

viced as part of the rear seat floor duct on bench seat

models, or the center seat floor duct on bucket seat
models.

(1) Remove the carpeting from the floor panel
transmission tunnel. Refer to Group 23 - Body for the
procedures.

(2) Remove the retainers that secure the ducts to
the floor panel transmission tunnel (Fig. 85) or (Fig.

86).

(3) Remove the duct(s) from the floor panel as
required.

(4) Reverse the removal procedures to install.

DEMISTER DUCT ADAPTER

(1) Roll the instrument panel assembly down, but
do not remove it from the vehicle. Refer to Instru­ment Panel Assembly in the Removal and Installa­tion section of Group 8E - Instrument Panel Systems
for the procedures.

(2) Disconnect the flexible demister duct hose from
the demister duct adapter on the top of the heater­A/C housing.

(3) Remove the two screws that secure the demis­ter duct adapter to the top of the heater-A/C housing
(Fig. 87).

Fig. 85 Rear Seat Floor Ducts Remove/Install - Split

Bench Seat

(4) Remove the demister duct adapter from the

heater-A/C housing.

(5) Reverse the removal procedures to install.

Tighten the mounting screws to 2.2 N·m (20 in. lbs.).

DEMISTER HOSE

(1) Remove the heater-A/C control from the instru-

ment panel. See Heater-A/C Control in the Removal

24 - 66 HEATING AND AIR CONDITIONING DN

REMOVAL AND INSTALLATION (Continued)

Fig. 86 Rear Seat Floor Ducts Remove/Install - Bucket Seat

Fig. 87 Demister Duct Adapter Remove/Install

and Installation section of this group for the proce­dures.

(2) Reach through the heater-A/C control opening
in the instrument panel to access and remove the
screw that secures the flexible demister duct hose to
the demister duct tee.

(3) Roll the instrument panel assembly down, but
do not remove it from the vehicle. Refer to Instru­ment Panel Assembly in the Removal and Installa­tion section of Group 8E - Instrument Panel Systems
for the procedures.

(4) Disconnect the flexible demister duct hose from
the demister duct adapter on the top of the heater­A/C housing.

(5) Remove the demister duct hose from the demis­ter duct tee near the underside of the instrument
panel top cover.

(6) Reverse the removal procedures to install.
Tighten the hose mounting screw to 2.2 N·m (20 in.
lbs.).

DEMISTER DUCTS AND OUTLETS

(1) Remove the instrument panel top cover from
the instrument panel. Refer to Instrument Panel Top
Cover in the Removal and Installation section of
Group 8E - Instrument Panel Systems for the proce­dures.

(2) Remove the screws (two - left side, three - right
side) that secure the demister ducts to the instru­ment panel top cover (Fig. 88).

(3) Using a trim stick or another suitable wide
flat-bladed tool, gently pry between the end of the
demister duct and the demister outlet flange to
release the duct from the outlet.

(4) Remove the demister ducts and the tee from
the instrument panel top cover.

(5) Squeeze the demister outlet flange from the
underside of the instrument panel top cover and
push it out through the top.

(6) Using a trim stick or another suitable wide
flat-bladed tool, gently pry between the end of the

DN HEATING AND AIR CONDITIONING 24 - 67

REMOVAL AND INSTALLATION (Continued)

(4) Remove the plenum adapter from the plenum
panel.

(5) When reinstalling the heater-A/C housing ple­num adapter to the plenum panel opening, be certain
that the snap features on each side of the adapter
are fully engaged with the sides of the plenum panel
opening. This must be a water tight connection to
prevent leaks.

(6) Reverse the remaining removal procedures to
complete the installation.

REAR OVERHEAD A/C OUTLET BEZEL

The rear overhead A/C outlet bezel is used only on
models with the optional rear overhead A/C unit. The
outlet barrels located in the bezel are only serviced
as a unit with the rear overhead A/C outlet bezel.

Fig. 88 Demister Ducts Remove/Install

demister duct and the demister outlet flange to
release the duct from the outlet.

(7) Remove the demister ducts and the tee from

the instrument panel top cover.

(8) Squeeze the demister outlet flange from the
underside of the instrument panel top cover and
push it out through the top.

(9) Reverse the removal procedures to install.
Tighten the mounting screws to 2.2 N·m (20 in. lbs.).

(1) Using a trim stick or another suitable wide
flat-bladed tool, gently pry between both ends of the
rear overhead A/C outlet bezel and the headliner to
release the two snap clip retainers that secure the
bezel to the rear overhead A/C unit housing (Fig. 90).

HEATER-A/C HOUSING PLENUM ADAPTER

(1) Remove the heater-A/C housing from the vehi­cle. See Heater-A/C Housing in the Removal and
Installation section of this group for the procedures.

(2) Slide the heater-A/C housing plenum adapter

(Fig. 89) all the way to one side of the plenum open­ing.

Fig. 89 Heater-A/C Housing Plenum Adapter

Remove/Install

(3) Pull downwards sharply and firmly on the
opposite side of the plenum adapter to disengage the
snap feature from the plenum opening.

Fig. 90 Rear Overhead A/C Outlet Bezel Remove/

Install

(2) Remove the rear overhead A/C outlet bezel

from the headliner mounting hole.

(3) Reverse the removal procedures to install.

ADJUSTMENTS

TEMPERATURE CONTROL CABLE

Any time the heater-A/C control or the tempera­ture control cable are removed and/or replaced, the
following procedure must be performed.

(1) The temperature control cable housing and core
must be installed at both the heater-A/C control and
the heater-A/C housing ends, and the heater-A/C con­trol must be installed in the instrument panel. See
Heater-A/C Control and Temperature Control Cable

24 - 68 HEATING AND AIR CONDITIONING DN

ADJUSTMENTS (Continued)

in the Removal and Installation section of this group
for the procedures.

(2) Rotate the temperature control knob on the
heater-A/C control so that the knob pointer is in the
12 o’clock position.

(3) Pull the temperature control knob straight out
from the heater-A/C control base until the perimeter
of the knob (not the knob pointer) protrudes about 6
millimeters (0.25 inch) from the face of the control
base.

(4) Rotate the temperature control knob to the 1
o’clock position. Push in on the knob slightly and con­tinue rotating the knob to its full clockwise stop. The
knob pointer should be aimed at a position about 8
millimeters (0.315 inch) beyond the end of the grad­uated red strobe temperature control graphic on the
face of the heater-A/C control base. If the knob is not
pointed to the correct position, go back to Step 3 and
repeat the adjustment procedure.

(5) Rotate the temperature control knob counter­clockwise until the knob pointer is in the 12 o’clock
position again.

(6) Push the temperature control knob straight in
towards the heater-A/C control base until the perim­eter of the knob (not the knob pointer) is flush with
the face of the heater-A/C control base.

(7) Rotate the knob to its full clockwise stop again.
The knob pointer should be aimed at the end of the
graduated red strobe temperature control graphic on
the face of the heater-A/C control base. If OK, go to
Step 9. If not OK, go back to Step 3.

(8) Rotate the knob to its full counterclockwise
stop and release the knob. If the knob springs back
from the counterclockwise stop, the self-adjuster clip
that secures the temperature control cable to the
blend-air door lever is improperly installed. See Tem­perature Control Cable in the Removal and Installa­tion section of this group for the procedures. If the
knob does not spring back, the temperature control
cable adjustment is complete.