INOP. AND/OR INTERMITTENT CENTER DIFFERENTIAL LOCKING SW

Models Affected: 1990 PONTIAC 6000 SE 3T40-A/THM A-1

BULLETIN COVERS: Figure 1 ---------------- An inoperative and/or intermittent Center Differential Locking Switch (43) due to moisture entry during the manufacturing process, which may cause the following concerns:

AWD LOCK indicator will remain on, but differential will not lock

ANTILOCK indicator will remain on and ABS operation would be disabled

Vehicles equipped with possible inoperative and/or intermittent differential locking switches were produced between the following VIN breakpoints:

1G2AJ54T6L202602 and 1G2AJ54T6L209333.

SERVICE PROCEDURE:

If an inoperative or intermittent switch is found, replace it with a new one. This procedure can be performed on vehicle.

SERVICE PARTS INFORMATION:

Refer to the following part number whenever replacement of this switch is necessary.

Part Number Description ----------- ----------- 8665329 Switch, Signal Differential Lock

Parts are currently available from GMSPO.

SERVICE MANUAL REFERENCE:

Whenever on-vehicle service is necessary to any HYDRA-MATIC 3T40-A (THM A-1), refer to Section 7A of your service manual.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.