
Bedienungs- und Wartungsanweisung
Operation and Maintenance Instructions
Thermo Top V
Mercedes Benz M-Klasse (BR 164) / M Class (MR 164)
Mercedes Benz GL-Klasse (BR 164) / GL Class (MR 164)
Mercedes Benz R-Klasse (BR 251) / R Class (MR 251)

Content
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Maintenance and Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Heater Unit Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Programming the Telestart Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . .21
Switching on the heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Switching off the heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Switching on via the Vehicle Display . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Switching off via the Vehicle Display . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Battery change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Fault Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

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Operation and Maintenance Instructions
Thermo Top V for Mercedes Benz M, ML, R Class
General Information
Dear Webasto customer,
We assume that the operation of your new heater unit was explained to your
complete satisfaction by the Workshop/Service station that installed it. In these
operating instructions we would like to give you an overview once again of the
use of the Thermo Top V heater unit.

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Maintenance and Safety Instructions
Within the scope of the European Directive 70/156/EWG type approvals have been
granted for the Thermo Top V water heating unit in accordance with
Directives 2001/56/EG (Heating) and 72/245/EWG (EMC).
The unit must be installed in accordance with the accompanying installation
instructions.
The heater unit must not be operated:
Danger of
Explosion and
Suffocation
• at filling stations and refueling systems.
• in places in which highly flammable gases or dust can
form, and in places in which highly flammable liquids or
solid materials are stored (e.g. near fuel, coal dust, wood
dust, grain warehouses, dry grass and leaves, cardboard,
paper, etc.)
• in enclosed spaces (e.g. garage), and not with the time
switch or Telestart.

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The heater unit must not:
The heater unit must:
• be exposed to temperatures higher than 120°C (storage
temperature). Exceeding this can cause permanent damage
to the electronics.
• be operated without at least 20% share of an anti-freeze
approved by the manufacturer in the coolant of the heat
exchanger circuit.
• be operated with the fuel and at the nominal voltage
indicated on the type plate.
• if a large amount of smoke is given off, there are unusual
burning noises or smells, be switched off by removing the
fuse. Before using the unit again, have it checked by trained
Webasto personnel.
• be operated for 10 minutes at least once each month with a
cold engine and the lowest blower setting. At the latest, at
the start of the cold season the heater unit must be tested
by a competent technician.

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Liability Waiver
• Not following the installation instructions and the
information contained therein release Webasto from liability.
This also applies for non-specialist repairs or when original
spare parts are not used. This will result in voiding the type
approval of the heater unit and consequently the general
operating permit / EU type approval.

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Heater Unit Operation
According to the equipment fitted, the heater unit can be operated from the
vehicle display, by a pushbutton or radio control Telestart.
The heater unit can also be operated via the telephone with the Webasto
Thermo Call option.
NOTE:
We recommend that the heating time is adjusted according to the driving time.
Heating time = Driving time
For example: With a driving time of approx. 20 minutes (one-way trip), we
recommend not exceeding a switch-on time of 20 minutes.
In Heating Mode, set the vehicle heating to "22 ºC - AUTO" before leaving the
vehicle.
NOTE:
The maximum operating time for the auxiliary heating is preset by the vehicle
manufacturer to 50 minutes. This can only be changed by a professional workshop
using Mercedes Star Diagnosis.

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Use
With the Webasto Telestart T80, the heater unit can be switched on and off
wirelessly at a range of up to 600 m. When switching on and off, the transmitter
should be held as high as possible and vertical (see picture).
When transmitting, do not cover the antenna with your hand.
The maximum operating time is preset by the vehicle software to 50 minutes.
The maximum range is increased in open spaces. In built-up areas, make
allowance for a reduced range.
A higher altitude can also increase the range.
NOTE:
When the fuel level reaches "RESERVE", the auxiliary heating can no longer be
operated.

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Programming the Telestart Transmitter
1. Place batteries into the battery compartment of the transmitter.
2. Remove fuse 1A (black) from the heater's fuse holder (voltage interruption).
3. Wait at least 5 seconds.
4. Replace fuse in heater's fuse holder and within 5 seconds press the OFF button
on the transmitter for at least 1 second.
5. Programming is completed.
A second or third hand-held transmitter can be programmed in the same manner.
NOTE:
The programming process can be repeated as often as necessary. The "oldest"
transmitter will be deleted each time.
1A
1A
min. 5 sec.
max. 5 sec.
min. 1 sec.
OFF

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Switching on the heater
Hold the transmitter with the aerial upright and press the
ON button until the LED lights up (approx. 1 second).
The operation indicator extinguishes:
– After the preset operating time has elapsed.
– After switching off with Telestart or pushbutton.
Switching off the heater
Hold the transmitter with the aerial upright and press the
OFF button until the LED lights up (approx. 1 second).

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Switching on via the Vehicle Display
Press the Menu button on the left of the
steering wheel until "Settings" appears.
M Models:
Press the Menu button again and then with
the up/down arrow keys choose the
"Heating" menu option.
R Models:
From the "Settings" menu, go straight to
"Auxiliary heating operating interval" at the
bottom of the menu.

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Use the +/- buttons on the right of the
steering wheel to select the switch on times
and the arrow keys and +/- buttons to
program the switch on time(s).
Before parking the vehicle, set the
following settings:
The temperature selection is to be set
on both sides to "High“.
If the preselect function has been
deactivated, select the "Preselect off"
menu option.

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Switching off via the Vehicle Display
The auxiliary heating cannot be switched off via the vehicle display, but only using
the pushbutton. If the auxiliary heating is switched on via the vehicle display, the
pushbutton does not light. To switch off, press the pushbutton 2x.
Indication
When the auxiliary heating is switched on with the pushbutton or the Telestart,
the pushbutton lights as an indicator.
NOTE:
If the auxiliary heating is switched on via the vehicle display, the pushbutton does
not light.

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Battery change
See also page 21: Programming the Telestart Transmitter.
Note
Return batteries of our products after use at the
point of purchase or in its immediate vicinity. Returning them is free. As end user you are legally
obliged to return used batteries.
Caution!
Risk of explosion if battery is replaced by an incorrect type! Dispose of the used batteries according
to the instructions. This product is subject of the European directive 2002/96EC and EN 50419.
Dispose information shall be given either at the
sample or in the user instruction.

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Troubleshooting
If a fault occurs, check the security and condition of the fuses and the connections.
If there is a malfunction, the heater unit switches to defect lock mode; there is no
error message on the timer display
.
Before you visit a Webasto Service station, try to clear the defect lock.
You can rectify the following faults yourself:
Fault Description Possible Cause Corrective Action
Heater unit switches itself
off automatically
(=fault shutdown)
No combustion after Start
and repeat Start, flame
goes out during
operation.
Heater unit switches off
and on again (not more
often than 2x)
Heater unit does not
switch on
Heater unit has no power Check the heater unit
power supply and the
grounding point
connection
Heater unit switches off
while heating
(=fault shutdown)
Heater unit has
overheated due to lack of
coolant
Refill coolant according
to manufacturer's
specifications

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Fault Reset
The defect lock is incorporated in the auxiliary heater fuse holder in the engine
compartment.
Note:
The heater unit is switched on when the fuse is replaced.
If this action does not correct the fault, please contact a Webasto Service station.
Power interruption
by removing the 20A
fuse (yellow)
Replace
the fuse
Briefly press the
ON button on
the left of the
transmitter
Replacing the fuse
The heater unit is
switched on
Power interruption
by removing the 20A
fuse (yellow)
approx.
3 sec.
wait
approx.
3 sec.
wait
On

Bei mehrsprachiger Ausführung ist
Deutsch verbindlich.
In multilingual versions the German
language is binding.
Webasto AG
Postfach 80
D - 82131 Stockdorf
Germany
Hotline: +49 (0)1805 - 707 400
(€ 0.14 aus dem deutschen
Festnetz)
e-mail: kundencenter@webasto.de
http://www.webasto.com
Subject to modification
© 2009 All Rights Reserved
IDENT.-NR. 9015325D