PARK BRAKE LIGHT REMAINS ON WHEN VEHICLE IS IN DRIVE

SUBJECT: PARK BRAKE LIGHT ON WITH VEHICLE IN "DRIVE" (ADDITION OF PARK BRAKE RETURN SPRING)

MODELS: 1991 P3 WITH C7P OPTION

THIS BULLETIN CANCELS AND REPLACES GMC TRUCK BULLETIN 91-5-143 (CORPORATE #165009). ALL COPIES OF 91-5-143 SHOULD BE DISCARDED.

Some 1991 P3 vehicles with C7P option may experience a condition of insufficient return force on the park brake lever to seat the park brake light switch in the off position. This results in the "park" light staying on while the vehicle is in the drive mode. In order to correct this condition, a second return spring should be installed per the following procedure.

SERVICE PROCEDURE: (FOR RETURN SPRING ADDITION) ------------------------------------------------ 1. Block wheels. Start engine and put transmission in neutral. Mark lock nut on actuator shaft and then tighten lock nut back to actuator to prevent any possible application of actuator. Then turn off engine and place the park brake foot lever in the release position.

2. Referring to figure 1, remove and retain the upper bolt on the park brake cable return spring bracket.

3. Attach (new) return spring (2) to (new) park brake cable return spring bracket (1).

4. Referring to view (A) for correct spring location, attach return spring (2) to the park brake clevis pin at its inboard side.

5. Align upper bolt with the upper hole in the park brake cable return spring bracket (1). Then reinstall bolt in original location and hand tighten.

6. Remove lower bolt from the original park brake cable return spring bracket and twist (new) park brake cable return spring bracket (1) until holes align. Then reinstall lower bolt and hand tighten.

7. Torque park brake cable return spring bracket bolts to 42-62 N-m (31-46 lbs. ft.).

8. Reset actuator lock nut to original position as marked in step 1.

9. Check function of spring by starting the vehicle and cycling vehicle gear shift lever between "P" park and "N" neutral.

SERVICE PARTS INFORMATION:

Part Number Description Quantity --------- ----------------------- -------- 15666394 Park Brake Cable Return 1 Spring Bracket

3889904 Park Brake Cable Return 1 Spring

Parts are currently available from GMSPO.

WARRANTY INFORMATION:

For vehicles repaired under warranty use:

Labor Operation: T7301 Labor Time: 0.4 hr.

NOTE: Labor Operation is coded to base vehicle coverage in the warranty system.

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.