IN-CAR SENSOR HOSE CAUSING LACK OF TEMPERATURE CONTROL

VEHICLES AFFECTED: 1989 and 1990 BUICK C/H MODELS

CONDITION

An inoperative or partially inoperative in-car sensor system has been found to be a possible cause of lack of temperature control and/or temperature overshoot.

The following should be checked if this condition is encountered on the subject vehicles.

CORRECTION

1. Assure the in-car sensor hose is properly connected at both the aspirator and in-car sensor ends. Assure there are no kinks in the hose.

2. Assure the aspirator is firmly seated in the HVAC case and that none of the four attaching legs are broken or the seal is damaged.

3. Assure the in-car sensor and the foam seal are properly seated. There must be no air leakage past the foam seal.

4. The instrument panel trim plate seal must be against the edge of the trim plate and provide a good seal between the trim plate and the instrument panel carrier. This seal assures the sensor gets an accurate air temperature sample from the passenger compartment. If this seal is mispositioned, air will be drawn from behind the instrument panel indicating an incorrect interior temperature to the sensor.

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.