A/C CONTROLS WARM AFTER VEHICLE IS PARKED 2-5 HOURS

SUBJECT: A/C CONTROLS WARM AFTER VEHICLE PARKED 2-5 HOURS (INSTALL NEW PROGRAMMER)

VEHICLES AFFECTED: 1991 "C" MODELS WITH C68 OPTION

CONDITION:

---------- Owners of some 1991 C Models with option "C68" may experience a condition where the HVAC does not immediately control the temperature properly. This normally occurs after the vehicle is driven in the morning then parked during cool ambients. Returning to the vehicle at mid day, less than five hours later, when ambients are twenty degrees or more warmer, the A/C will not properly cool the vehicle.

CAUSE:

------ Programmers with Software Versions 01 or 02 (Buick) or 01-06 (Olds) prohibit the outside temperature from updating until five hours have elapsed after the ignition is turned off. Vehicles with the above programmer must be driven above 10 mph for the outside temperature display to update. It may take up to ten minutes to fully update at 50 mph.

CORRECTION:

------------ A new programmer Part No. 16165979 (Buick) 16165978 (Olds) has been released for service. The new software version will be 03 (Buick) 07 (Olds). This programmer will allow the temperature display to update after the ignition has been off for 2 1/2 hours minimizing the effect of rising ambient temperatures.

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.