Coolant Temperature - Warning Light Comes On

Applies To 5000S
19 Group
1984

Subject Key Points Number

Cooling System Modification to prevent coolant temperature
warning light from coming on during normal 85-19-01

Part Identifier vehicle operation
(Supersedes Group 19 85-01 April 19, 1985) C July 12, 1985


If the coolant temperature warning light comes on without the engine overheating while operating with the A/C on, the following modifications can be performed:

Parts required

Part No. Description

431 959 455L Fan motor (350W)
321 959 481 D Thermo Switch
321 906 231 A Housing
321 959 459 Grommet
111 971 959 Connector
N 900 842 02 Connector

Work Procedure:

- exchange positions of wires 1 and 2 in radiator fan wiring connector housing
- remove 2-prong far thermoswitch from radiator and replace with new thermoswitch, Part No. 321 959 481D
- cut rubber grommets off thermoswitch wiring and discard

Thermoswitch Housing Part No. 321 906 231A:

Note The existing thermoswitch wires plus an additional wire (see below) will be connected to the new thermoswitch through grommet, Part

No. 443 959 459A and connector housing, No. 321 906 231A.

- route a 1400 mm (55-1/8 in) green/blue, 20 ga. wire through a protective sheath from position 1 of the thermoswitch connector housing to:

Auxiliary Fuse Panel (Front):

For vehicles up to VIN 445 095 313 terminal 6 of the fan motor relay 10 on the auxiliary relay panel (arrow)

Fuse/Relay Panel (Rear):

For vehicles from VIN 44 E 095 314:

terminal 6 of the 8-prong housing on the fuse/relay panel (arrow)

Note

The red/white wire at these locations is to be removed from the terminal and taped.

- replace fan motor
Labor operation: 19 08 21 3 Diagnosis:
Repair: 160 T.U.
Quality check: 20 T.U.
Total: 180 T.U.