HTR.-A/C CONTROL ASSY LOCK-UP OR MAY WORK IN REVERSE

SUBJECT: HEATER-A/C CONTROL ASSEMBLY MAY LOCK UP OR OPERATE IN REVERSE (REPLACE HEATER-A/C CONTROL ASSEMBLY)

VEHICLES AFFECTED: 1988-1991 OLDSMOBILE CUTLASS SUPREME WITH OPTION CODE C68

Condition:

---------- The Heater-Air Conditioning Control Assembly on the 1988-91 Oldsmobile W-Car may lock up (not respond to any inputs), or may cause the temperature door to go to full hot when full cold is requested. This condition may occur when the temperature door actuator is replaced.

Cause:

------ Software conditions in the control assembly. These conditions were corrected for the 1992 model year.

Correction:

----------- Replace the Heater-Air Conditioning Control Assembly with the 1992 part number. These numbers are:

16171487 Without Rear Defrost 16171488 With Rear Defrost

To temporarily correct this condition while the part is being ordered, perform the following steps:

1. With ignition off, remove the 15 amp "ELEC" fuse (fuse #2).

2. Start engine.

3. With engine on, reinstall the fuse.

For vehicles repaired under warranty use:

Existing labor operation to replace the Heater-Air Conditioning Control Assembly.

To perform the temporary operation, use Labor Time: 0.2 Hrs.

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.