For 1990-2009 cars

# HVAC SYSTEM WILL NOT HEAT UP OR COOL DOWN

#### SUBJECT: HVAC SYSTEM WILL NOT HEAT UP OR COOL DOWN SUFFICIENTLY (ADJUST TEMPERATURE CONTROL CABLE)

#### MODELS: 1993-95 CHEVROLET CAMARO 1993-95 PONTIAC FIREBIRD

#### CONDITION:

HVAC SYSTEM MAY NOT HEAT UP OR COOL DOWN SUFFICIENTLY.

#### CAUSE:

THE TEMPERATURE CONTROL DOOR MAY NOT BE CLOSING COMPLETELY BECAUSE THE TEMPERATURE CONTROL CABLE ASSEMBLY MAY REQUIRE REPLACEMENT OR ADJUSTMENT.

#### CORRECTION:

1. REMOVE RIGHT INSTRUMENT PANEL SOUND INSULATOR ASSEMBLY.

2. REMOVE (1) SCREW THAT RETAINS THE TEMPERATURE CONTROL CABLE TO THE BOTTOM OF THE HVAC MODULE. REMOVE THE CABLE FROM THE MODULE TO OBSERVE THE POSITION OF ADJUSTMENT AND CHECK THE DATE CODE.

3. WITH THE CABLE STILL ATTACHED TO THE HVAC CONTROL HEAD, CYCLE THE TEMPERATURE KNOB BETWEEN FULL COLD AND FULL HOT TO OBSERVE FOR PROPER MOVEMENT AT THE MODULE END. IF A BINDING IS NOTED OR THE CABLE DOES NOT ROTATE FREELY, REPLACE THE CABLE. IF THE CABLE DOES **NOT** BIND AND ROTATES FREELY, SET THE TEMPERATURE KNOB TO THE MID DETENT POSITION HALFWAY BETWEEN FULL COLD AND FULL HOT.

4. CHECK THE DATE CODE OF THE CABLE. THIS FOUR DIGIT NUMBER SHOULD BE FOUND EITHER ON THE CABLE PULLEY OR HOT STAMPED ON THE CABLE CONDUIT ABOUT 4" FROM THE PULLEY END (FIGURE 1). FOR DATE CODE NUMBERS 4001 AND LESS PROCEED WITH SECTION I. FOR NUMBERS LARGER THAN 4001 SKIP TO SECTION II.

SECTION I (FOR CABLE DATE CODES LESS THAN 4001)

1. FIGURE 2 SHOWS A CABLE THAT IS SIGNIFICANTLY MISADJUSTED. AS CAN BE SEEN, (WITH THE TEMPERATURE KNOB SET TO THE MID POSITION) THE PULLEY IS SKEWED TOWARD THE FULL HOT SIDE. THE PROPER ADJUSTMENT WILL SHOW THE PULLEY SKEWED (5-10 DEGREES) TOWARD THE FULL COLD SIDE (FIGURE 3). THE 5-10 DEGREES SKEWING TOWARD THE FULL COLD SIDE (WITH THE CONTROL KNOB IN THE MID POSITION) ASSURES THAT THE DOOR WILL BE FULLY CLOSED WHEN THE KNOB IS IN THE FULL COLD POSITION. AIR LOADING ON THE DOOR IN THE FULL HOT POSITION ASSURES THAT THE DOOR WILL BE CLOSED WHEN IN FULL HOT.

2. WITH SOME CABLES, THERE IS NOT ENOUGH TENSION ON THE SPRING TO KEEP THE SPRING FROM SHIFTING WHEN THE KNOB IS TURNED AND THE BLOWER IS ON HIGH. THE BALL SLUGS ON THE WIRES MAY HAVE BEEN IMPROPERLY STAKED AND THE SPRING NEEDS TO BE TENSIONED AND THE CABLE READJUSTED TO FUNCTION PROPERLY. A SMALL SPRING RETAINER, P/N 10282056, WILL BE NEEDED.

3. WITH THE TEMPERATURE KNOB STILL IN THE MID POSITION, REMOVE THE SPRING FROM THE ASSEMBLY WITH A PAIR OF SMALL NEEDLE-NOSE PLIERS OR A SMALL SCREW DRIVER (FIGURE 4).

4. BEFORE ATTACHING THE RETAINER, SKEW THE PULLEY (5-10 DEGREES) TOWARD THE FULL COLD POSITION (SEE FIGURE 5 AND 6) AND SNAP THE SPRING INTO POSITION. THE CABLE SHOULD NOW BE IN THE CORRECT ADJUSTMENT POSITION FOR THE MID POINT ON THE TEMPERATURE KNOB BETWEEN FULL COLD AND FULL HOT.

#### IMPORTANT: THE SPRING DOES NOT HAVE TO BE CENTERED ABOUT THE PULLEY.

5. USING THE SPRING RETAINER, INSERT ONE END INTO THE SPRING AND PULLEY AS SHOWN IN FIGURES 6 AND 7.

6. SLIGHTLY COMPRESS THE SPRING AND INSERT THE OTHER END OF THE RETAINER (SEE FIGURE 7). ANY SLACK IN THE WIRES SHOULD BE TAKEN UP BY THE RETAINER AND SPRING. IT IS **NOT** NECESSARY TO OVER-TIGHTEN THE SPRING WITH THE RETAINER. IMPORTANT: IF THE RETAINER PUTS TOO MUCH TENSION ON THE WIRES, THE CABLE EFFORT MAY SIGNIFICANTLY INCREASE.

7. PUSH THE RETAINER DOWN INTO THE PULLEY CUP TO KEEP THE SPRING IN POSITION AND TO INSURE THAT THE RETAINER WILL NOT DRAG ON THE BOTTOM OF THE HVAC MODULE WHEN THE CABLE IS INSTALLED. SMALL NEEDLE-NOSE PLIERS CAN BE USED TO PUSH THE RETAINER ALL THE WAY INTO THE PULLEY (SEE FIGURE 8).

8. WITH THE RETAINER PROPERLY INSTALLED AND THE TEMPERATURE KNOB STILL IN THE MID POSITION BETWEEN FULL HOT AND FULL COLD, THE CABLE SHOULD LOOK AS SHOWN IN FIGURE 8. CYCLE THE TEMPERATURE CONTROL KNOB FROM FULL COLD TO FULL HOT. THE TEMPERATURE CONTROL DOOR SHOULD MAKE A THUMPING SOUND WHEN CLOSING IF IT IS WORKING PROPERLY.

9. REINSTALL THE CABLE, CABLE SCREW AND RIGHT INSTRUMENT PANEL SOUND INSULATOR ASSEMBLY.

SECTION II (FOR CABLE DATE CODES LARGER THAN 4001)

THE CABLE MAY SIMPLY NEED TO BE ADJUSTED.

1. FIGURE 9 SHOWS A CABLE THAT IS NOT PROPERLY ADJUSTED. AS CAN BE SEEN, (WITH THE TEMPERATURE KNOB SET TO THE MID POSITION) THE PULLEY IS SKEWED SLIGHTLY TO THE FULL HOT SIDE. THE PROPER ADJUSTMENT WILL SHOW THE PULLEY SKEWED (5-10 DEGREES) TOWARD THE FULL COLD SIDE (WITH THE CONTROL KNOB IN THE MID POSITION) ASSURES THAT THE DOOR WILL BE FULLY CLOSED WHEN THE KNOB IS IN THE FULL COLD POSITION. AIR LOADING ON THE DOOR IN THE FULL HOT POSITION ASSURES THAT THE DOOR WILL BE CLOSED WHEN IN FULL HOT.

2. WITH THE TEMPERATURE KNOB STILL IN THE MID POSITION, REMOVE THE SPRING FROM THE ASSEMBLY WITH A PAIR OF SMALL NEEDLE-NOSE PLIERS OR A SMALL SCREW DRIVER (FIGURE 11).

3. SKEW THE PULLEY 5-10 DEGREES TOWARD THE FULL COLD POSITION AND SNAP THE SPRING BACK INTO THE PULLEY. A PROPERLY ADJUSTED CABLE (WITH THE TEMPERATURE KNOB IN THE MID POSITION - HALFWAY BETWEEN FULL COLD AND FULL HOT) WILL LOOK LIKE FIGURE 10.

4. CYCLE THE TEMPERATURE CONTROL KNOB FROM FULL COLD TO FULL HOT. THE TEMPERATURE CONTROL DOOR SHOULD MAKE A THUMPING SOUND WHEN CLOSING IF IT IS WORKING PROPERLY.

5. REINSTALL THE CABLE, CABLE SCREW AND RIGHT INSTRUMENT PANEL SOUND INSULATOR ASSEMBLY. PROCEDURE COMPLETE.

SERVICE PARTS INFORMATION

P/N DESCRIPTION

10281598 TEMPERATURE CONTROL CABLE ASSEMBLY (CHEV ONLY) 10281599 TEMPERATURE CONTROL CABLE ASSEMBLY (PONTIAC ONLY) 10282056 SPRING RETAINER

#### PARTS INFORMATION:

PARTS ARE EXPECTED TO BE AVAILABLE ON 5/1/95 AT GMSPO.

#### WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR OPERATION: D0447 - TO REPLACE CABLES USE PUBLISHED LABOR OPERATION TIME. LABOR TIME: 0.3 HR. TO INSTALL SPRING RETAINER

FIGURES: 11 (3 PAGES)

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.

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