For 1990-2009 cars

# REDUCED HEATER PERFORMANCE ON THE DRIVERS SIDE

REVISION: 01/12/96

THIS BULLETIN IS BEING REVISED TO ADD THE 1996 MODEL YEAR. PLEASE DISCARD CORPORATE BULLETIN NUMBER 53-11-01 (GROUP REFERENCE 1 - HVAC). *********************************************************************

#### SUBJECT: REDUCED HEATER PERFORMANCE ON THE DRIVER'S SIDE (REALIGN SOUND INSULATOR/HEATER DUCT)

#### MODELS: 1995-96 BUICK RIVIERA 1995-96 OLDSMOBILE AURORA

#### CONDITION:

SOME OWNERS MAY COMMENT ON REDUCED HEATER PERFORMANCE ON THE DRIVER'S SIDE DUE TO THE LACK OF AIR FLOW FROM THE HEATER OUTLETS.

#### CAUSE:

MISALIGNMENT OF SOUND INSULATOR/HEATER DUCT TO INTERMEDIATE HEATER DUCT.

#### CORRECTION:

FOLLOW PROCEDURE LISTED BELOW TO INSURE THAT THE SOUND INSULATOR/ HEATER DUCT IS PROPERLY ALIGNED TO THE INTERMEDIATE HEATER DUCT.

DIAGNOSIS -

1. SET HVAC CONTROLS TO THE MANUAL HEATER MODE, SET TEMPERATURE TO 90 DEGREES FAHRENHEIT (32 DEGREES CELSIUS) AND BLOWER MOTOR ON HIGH SPEED.

2. CHECK FOR AIR FLOW FROM HEATER OUTLETS IN SOUND INSULATOR. THERE ARE 3 HOLES NEAR LAMP ON SOUND INSULATOR. REFER TO FIGURE 1.

3. IF LITTLE OR NO AIR FLOW IS PRESENT, REMOVE 3 SCREWS RETAINING THE SOUND INSULATOR/HEATER DUCT.

4. INSPECT THE TOP SIDE OF THE SOUND INSULATOR HEATER DUCT AT THE INLET TO THE HEATER DUCT WHICH IS MOLDED INTO THE SOUND INSULATOR.

5. IF THE TOP OF THE HEATER DUCT OPENING ON THE SOUND INSULATOR HAS BEEN CRUSHED, THEN IT WAS IMPROPERLY ALIGNED WITH THE INTERMEDIATE HEATER DUCT. THE INTERMEDIATE HEATER DUCT IS A TRANSITION DUCT FROM THE HVAC MODULE TO THE LEFT SOUND INSULATOR/HEATER DUCT. THIS MISALIGNMENT CAUSES A SEVERE LOSS OF AIR FLOW TO THE LEFT HAND SOUND INSULATOR/HEATER DUCT.

REPAIR PROCEDURE -

REFER TO FIGURE 2.

1. REMOVE THE LAMP FROM THE SOUND INSULATOR/HEATER DUCT.

2. REMOVE SOUND INSULATOR/HEATER DUCT FROM VEHICLE.

3. RESHAPE THE INLET TO THE SOUND INSULATOR/HEATER DUCT WITH YOUR HANDS.

4. REPOSITION THE FOAM SEALS AROUND THE EDGE OF THE INLET TO THE SOUND INSULATOR/HEATER DUCT.

#### IMPORTANT: THE INTERMEDIATE HEATER DUCT DOES NOT NEED TO BE REMOVED FROM THE VEHICLE.

INSTALLATION OF SOUND INSULATOR/HEATER DUCT -

REFER TO FIGURE 2.

1. INSTALL LAMP INTO LAMP SOCKET.

2. LIFT SOUND INSULATOR/HEATER DUCT OVER THE PARKING BRAKE LEVER AND INSTALL THE LEFT FORWARD EDGE INTO THE PLASTIC CLIP.

3. POSITION THE INTERMEDIATE HEATER DUCT AS FAR REARWARD IN THE VEHICLE AS POSSIBLE. THE ASPIRATOR HOSE MAY HAVE TO BE REPOSITIONED IF IT INTERFERES WITH THE INTERMEDIATE HEATER DUCT.

4. PUSH SOUND INSULATOR/HEATER DUCT AS FAR FORWARD AS POSSIBLE.

5. INSTALL SOUND INSULATOR/HEATER DUCT UP INTO THE FINAL INSTALLED POSITION.

#### IMPORTANT: MAKE SURE THAT THE INTERMEDIATE HEATER DUCT AND THE MOLDED HEATER DUCT ARE PROPERLY ALIGNED. PULLING THE INTERMEDIATE HEATER DUCT REARWARD AND PUSHING THE SOUND INSULATOR/HEATER DUCT FORWARD SHOULD ALLOW THE PROPER ALIGNMENT OF THE TWO PIECES. REFER TO FIGURE 3.

6. INSTALL 3 ATTACHING SCREWS.

#### SYSTEM CHECK:

1. POSITION THE HVAC CONTROLS AS DESCRIBED IN THE DIAGNOSIS AND RECHECK THE AMOUNT OF AIRFLOW. THERE SHOULD BE A SIGNIFICANT IMPROVEMENT IN THE AMOUNT OF AIRFLOW.

2. TO ENSURE MAXIMUM AIRFLOW OUT OF THE DUCTS, CHECK FOR LEAKAGE AROUND THE JUNCTION BETWEEN THE MOLDED DUCT ON THE SOUND INSULATOR AND THE INTERMEDIATE DUCT. AN EXTRA PIECE OF FOAM MAY HAVE TO BE INSTALLED TO PROVIDE AN AIRTIGHT SEAL. A TIGHT SEAL BETWEEN THESE 2 DUCTS WILL IMPROVE AIRFLOW PERFORMANCE OUT OF THE SMALL OPENING ON THE SOUND INSULATOR/HEATER DUCT WHICH DIRECTS AIR TO THE DRIVER'S FOOT.

#### WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER: C2421 USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 3

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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