Heater - Revised Low Heat Delivery Diagnosis

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NUMBER: 91-T-201

CORP.REF.NO: 131104

DATE: October 1991

SECTION: 1A, 1B


SUBJECT:
SERVICE MANUAL UPDATE - REVISED PROCEDURE FOR LOW HEAT DELIVERY RELATED DIAGNOSIS - ENHANCED TEMP. CONTROL CABLE ADJUSTMENT

MODELS/YEARS:
1989-91 CALAIS


On customer comments of low heater output on 1989-91 Calais, before replacing a suspected defective engine cooling thermostat, proper diagnosis of the conditon must be performed to avoid the possibility of a repeat repair. Follow "Diagnosis" as shown in Section 1A/1B of the appropriate Service Manual. After completing the diagnosis, use the following as a guide to the next corrective step:

^ If the diagnosis indicates a defective thermostat, refer to Section 6B for replacement.
^ If the diagnosis indicates a defective temperature control cable, refer to Section 1A/1B for replacement.
^ If the diagnosis indicates the temperature control cable is no longer "snapped" into its retainer, refer to "Temperature Control Cable Repair" in the 1991 Service Manual, Sections 1A/1B.
^ If the diagnosis indicates that the temperature control cable is out of adjustment, refer to the following procedure to repair.

TEMPERATURE CONTROL CABLE ADJUSTMENT PROCEDURE

CONDITION 1: "Spring back" off full "hot" temperature control position (or not attaining full "cold" temperature door position).

CONDITION 2: "Spring back" off full "cold" temperature control position (or not attaining full "hot" temperature door position).





CAUSE: The temperature control cable "clip" needs adjustment. Refer to the illustration for correct gripping of the "clip" during adjustment.

CORRECTION 1: Grip "clip" at module end of cable while pulling temperture control lever to "hot" position.

CORRECTION 2: Grip "clip" at module end of cable while pushing temperture control lever to "cold" position.

Notice: Failure to "clip" correctly will damage its ability to hold position on the cable. The temperature control cable must be replaced if "clip" retention fails.

Verify correct adjustment after repair by observing for no, or very little, "spring back" of the temperature control lever and listening for temperature door "slam" when the control lever is moved to full hot and cold positions quickly.

Please note in your copies of the appropriate Service Manuals in Sections 1A and 1B, under "Temperature Control Cable", with these new adjustment instructions.