C.E. Niehoff & Co. A2-341, A2-346 Regulator Installation

A2-341 & A2-346 28 V Regulators

with A9-4036 Temperature-Voltage Sense/

J1939 Harness

Installation Instructions

FOR PARALLEL OPERATION, SEE SEPARATE INSTRUCTIONS PACKED WITH SPECIAL WIRING HARNESS

These 28 V regulators can be used with or without A9-4036 temperature-voltage sense/J1939 harness

NOTICE

from the vehicle.

• When A9-4036 temperature-voltage sense/J1939 harness is not connected, regulator will operate
in fi xed voltage setting determined by the select switch position on the bottom of the regulator.
See column 2 in Table 1.

• When A9-4036 temperature-voltage sense/J1939 harness is connected, regulator will automatically
optimize the charge voltage for battery type based on temperature. See column 3 in Table 1 and
select switch position based on battery type.

Table 1 – Regulator Select Switch Position

A9-4036 Harness Not Connected

(Voltage Select)

Switch Position

See NOTICE above

Position 1 27.5 V

Position 2 28.0 V
Position 3 28.5 V
Position 4 29.0 V

1. Before installing, turn regulator over and select
appropriate switch position (see NOTICE above and
Table 1 and Figure 1).

2. Using screws supplied, mount flat-base regulator on
the alternator. Torque screws to 8.5 Nm/75 lb in.
See Figure 2.

3. Plug alternator-to-regulator harness securely into
6-socket connector on regulator.

4. See Figure 2:

• If using A9-4036 temperature-voltage sense/
J1939 har ness:

1) Remove cap from regulator and plug harness
connector into 10-pin connector.

2) Harness length is 182 inches, enough to reach
battery compartment in most vehicles. Unused
harness length should be coiled up. Use cable
ties every 12-14 inches to securely support
harness between regulator and battery
compartment. If harness length must be
shortened:
a) Black wire—cut off and save first
6 inches on terminal end to reattach.
Cut length off of remaining black wire.
Crimp and solder two ends and seal with
insulatable butt splice.
b) Red wire—cut to desired length and use
terminal to connect.

3) Attach terminal from black wire in A9-4036
harness to battery negative post and terminal
from red wire to 28 V battery positive post.

4) If using J1939 connector on harness, connect
as indicated by vehicle manufacturer.

• If not using A9-4036 temperature-voltage sense/
J1939 harness, keep cap on regulator.

2

A9-4036 Harness Connected

(Battery Type)

See NOTICE above

Maintenance (D Category)

Maintenance-Free (Group 31)

AGM

DO NOT USE POSITION #4

5. These regulators can function with or without vehicle
ignition. When necessary, connect IGN terminal on
regulator to vehicle ignition to provide battery voltage
when engine is running. Circuit should be off (no volt­age present) when vehicle ignition is off or engine is
not running. Use proper ring terminal and torque M5
terminal nut to 4.5 Nm/40 lb in.

6. P terminal on regulator taps AC voltage, typically half
the charge voltage. If required, connect P terminal on
regulators to tachometer or relay. Torque M6 termi­nal nut on regulator to 4.5 Nm/ 40 lb in.

7. D+ terminal on regulators provides 28 VDC sense
voltage to multiplex controller. Maximum current
from D+ can be no more than 5 amps. If required,
connect D+ terminal to controller through a relay.
The relay coil must be diode-protected and rated for
proper voltage. Use proper ring terminal. Torque M6
terminal nut to 4.5 Nm/40 lb in.

1

3

Figure 1

Alternator-to-regulator

See step 4

connector

IGN Terminal

D+ Terminal

LED

Figure 2 – A2-341 or A2-346 Regulator

P Terminal

4

C. E. Niehoff & Co. • 2021 Lee Street • Evanston, IL 60202 Tech Services Hotline [phone]

Page 1 of 1

II183A