[Manitcor]

SUBJECT: AIR TEMPERATURE FROM HVAC OUTLETS DOES NOT CHANGE OR BLOWS COLD (REPLACE TEMPERATURE VALVE DOOR)

MODELS: 1997 BUICK CENTURY, REGAL 1997 CHEVROLET CORVETTE, VENTURE 1997 OLDSMOBILE SILHOUETTE 1997 PONTIAC GRAND PRIX, TRANS SPORT

CONDITION:
SOME OWNERS MAY COMMENT THAT THE AIR TEMPERATURE FROM THE INSTRUMENT PANEL AND HEATER OUTLETS DOES NOT CHANGE OR BLOWS COLD.

CAUSE:
THE TEMPERATURE VALVE DOOR SHAFT MAY BE FRACTURED ON SOME VEHICLES CAUSING STICKING OR NO MOVEMENT OF THE DOOR. THIS CONDITION MAY SHOW UP ON RPO CJ2 SYSTEMS AS A DIAGNOSTIC CODE B0446 OR B0441. THE RPO CJ3, C60 AND C41 SYSTEMS DO NOT HAVE THE CAPABILITIES TO SET DIAGNOSTIC CODES. VERIFICATION OF THIS CONDITION CAN BE DONE BY REMOVING THE TEMPERATURE VALVE MOTOR AND PHYSICALLY HAND TURNING THE SHAFT TO DETERMINE TEMPERATURE CHANGE, BINDING OR LOSS OF FUNCTION.

IMPORTANT:
RPO CODES ARE LOCATED ON THE SERVICE PARTS IDENTIFICATION LABEL.

CORRECTION:
REPLACE THE TEMPERATURE VALVE DOOR.

PROCEDURE -
1. FOLLOW THE A/C EVAPORATOR CORE REPLACEMENT PROCEDURES IN SECTION 1B OF THE APPROPRIATE SERVICE MANUAL.
2. ONCE THE CASE IS SPLIT APART, THE TEMPERATURE VALVE DOOR WILL BE VISIBLE IN FRONT OF THE EVAPORATOR.
3. BEFORE REMOVING THE DOOR(S) IN BOTH SYSTEMS, TURN DOOR(S) UPWARD PARALLEL WITH THE EVAPORATOR AND NOTE THE DETAIL IN THE SEALS FOR INSTALLATION OF THE NEW DOOR(S).
4. THE DUAL ZONE (CJ2, CJ3) DOOR CAN BE REMOVED BY LIFTING THE SHAFT AT THE CENTER TO DISENGAGE THE TWO (2) PIECE DOOR.
5. ON THE SINGLE ZONE (C60, C41) DOOR, CAREFULLY SPREAD THE CASE AND SLIDE THE DOOR TO THE SIDE EXPOSING THE SHORT END OF THE SHAFT AND LIFT OUT OF CASE.
6. INSTALL THE NEW TEMPERATURE VALVE DOOR REVERSING THE PRIOR PROCEDURES.

IMPORTANT:
SEALING OF THE CASE IS VERY IMPORTANT, THEREFORE SEAL KIT P/N 52478813 (KIT 1) MUST BE ORDERED AND ALL OF THE SEALS INSTALLED ANYTIME THE CASE IS SEPARATED FOR A REPAIR.
7. FOLLOW THE A/C EVAPORATOR CORE INSTALLATION PROCEDURES IN SECTION 1B OF THE APPROPRIATE SERVICE MANUAL.
8. ONCE THE INSTALLATION IS COMPLETE, CYCLE HVAC SYSTEM MODES FOR PROPER OPERATION.

PARTS INFORMATION:
P/N DESCRIPTION QTY. === =========== ====
52469884 VALVE, TEMP (C60, C41) 1
52477971 VALVE, TEMP KIT (CJ2, CJ3) 1
52478813 SEAL, HVAC CASE (KIT 1) 1

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

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.

COPYRIGHT 1997 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.