A/C - Lack of Temperature Control/Overshoot

90oldsmobile05
SUBJECT IN-CAR SENSOR HOSE CAUSING LACK OF
TEMPERATURE CONTROL REPAIR PROCEDURE


MODELS/YEARS 1989 AND 1990 EIGHTY-EIGHT AND NINETY-EIGHT
MODELS WITH AUTOMATIC AIR-CONDITIONING (C-68)
NUMBER: 90-T-73

CORP.REF.NO: 001203

DATE: March 1990

SECTION: 1C

ILLUSTRATION:

CONDITION:

A pinched or disconnected in-car sensor hose has been found to be a possible cause of lack of temperature control and/or temperature overshoot on the subject vehicles. (see illustration)

To check for this condition, run the A/C Blower Fan on high while holding a light weight piece of paper over the sensor opening. (Sensor opening is six rectangular holes in the cluster trim plate.) If the sensor hose is not pinched or disconnected, the paper will be drawn toward the opening when held just slightly above it. Also, the paper will lightly stick to the opening if the system is drawing air through the opening properly. If no air flow is noted at the sensor opening, proceed with the following.

CORRECTION:

The pinch point in the sensor hose has most often been between the upper level distributor duct and the A/C - Defroster mode door opening. With the glove compartment lowered, this pinch area can be seen. Access to relieve the pinch can be gained either through the glove compartment opening or the in-board right upper level duct opening. If the sensor hose is not pinched in this area and air flow through the sensor opening is not present, remove the I/P trim plate and A/C control head to expose the entire length of the sensor hose. Check the connection of the sensor hose at both the in-car sensor and the aspirator. If the hat shaped in-car sensor adapter under the cluster trim plate is mispositioned, it also can cause the lack of air flow.

IMPORTANT: Assure the aspirator hose does not become disconnected when reinstalling the A/C control head. In all cases, after a repair has been made, assure proper air flow to the sensor has been restored.

WARRANTY INFORMATION:

Labor Operation: D0500
Labor Time: 0.7 Hour
Trouble Code: 92