AIR CONDITIONING ODOR AT START UP IN HUMID CLIMATES

REVISION: 12/06/97

THIS BULLETIN IS BEING REVISED TO UPDATE THE WIRING DIAGRAMS, ADD THE CORVETTE (WITH RPO C60) AND DELETE MEDIUM/HEAVY DUTY TRUCKS. PLEASE DISCARD CORPORATE BULLETIN NUMBER 53-12-12 (GROUP 1 - HVAC). ----------------------------------------------------------------------

SUBJECT: AIR CONDITIONING ODOR AT START UP IN HUMID CLIMATES (DISINFECT EVAPORATOR CORE, INSTALL DELAYED BLOWER CONTROL PACKAGE)

MODELS: 1993-96 PASSENGER CARS (EXCEPT GEO) 1993-96 LIGHT DUTY TRUCKS (EXCEPT TRACKER)

CONDITION:

SOME OWNERS MAY COMMENT ON ODORS EMITTED FROM THE AIR CONDITIONING SYSTEM, PRIMARILY AT START UP IN HOT, HUMID CLIMATES.

CAUSE:

THIS ODOR MAY BE THE RESULT OF MICROBIAL GROWTH ON THE EVAPORATOR CORE. WHEN THE BLOWER MOTOR FAN IS TURNED ON, THE MICROBIAL GROWTH MAY RELEASE AN UNPLEASANT MUSTY ODOR INTO THE PASSENGER COMPARTMENT.

CORRECTION:

TO REMOVE ODORS OF THIS TYPE, IT IS NECESSARY TO ELIMINATE THE MICROBIAL GROWTH AND PREVENT ITS RECURRENCE. TO ACCOMPLISH THIS, THESE TWO PROCEDURES MUST BE COMPLETED.

- DEODORIZE THE EVAPORATOR CORE USING DEODORIZING AEROSOL KIT, P/N 12377951 (AC DELCO 15-102).

- INSTALL THE NEW A/C DELAYED BLOWER CONTROL PACKAGE, P/N 12370470, (AC DELCO 15-8632).

THE BLOWER CONTROL PACKAGE WILL ENABLE THE BLOWER TO RUN AT HIGH SPEED FOR FIVE (5) MINUTES. IT WILL DO SO APPROXIMATELY FIFTY (50) MINUTES AFTER THE IGNITION HAS BEEN TURNED OFF IF THE COMPRESSOR HAD BEEN ENGAGED FOR FOUR (4) OR MORE MINUTES PRIOR TO SHUTTING OFF ENGINE. BY DOING SO, THE EVAPORATOR CASE AND CORE ARE DRIED OUT, REDUCING THE CHANCES OF A RECURRING A/C ODOR.

PROCEDURE -

1. VISUALLY INSPECT THE AIR CONDITIONING EVAPORATOR DRAIN HOSE FOR OBSTRUCTIONS OR WORKING CONDITION.

2. APPLY DEODORIZING AEROSOL AS DESCRIBED IN THE INSTRUCTIONS SUPPLIED WITH THE KIT. ONCE THE DEODORIZER HAS BEEN APPLIED, SOME OF THE MIXTURE MAY OVERFLOW FROM THE DRAIN HOSE.

3. THE FOLLOWING CHART IDENTIFIES SPECIFIC INSTRUCTIONS FOR EACH VEHICLE. THIS CHART WILL IDENTIFY THE PROPER DEODORIZING PROCEDURE, TEMPLATE AND WIRING DIAGRAM. DEODORIZING THE EVAPORATOR CASE CAN EASILY BE DONE BY REMOVING THE BLOWER MOTOR RESISTOR AND TAPE OFF OPENING. THE NOZZLE CAN NOW BE INSERTED THROUGH A PIERCED HOLE IN THE TAPE TO DEODORIZE THE EVAPORATOR CASE. FOR SOME OF THE VEHICLES SPECIFIED BELOW, A DRILLING PROCEDURE IS IDENTIFIED IN THE DEODORIZING INSTRUCTIONS. THIS TYPE OF ALTERNATIVE PROCEDURE AND OTHERS CAN BE DONE BY USING THE REFERENCED TEMPLATES IN THE CHART.

4. COMPLETE DETAILED INSTALLATION INSTRUCTIONS ARE SUPPLIED WITH THE BLOWER CONTROL PACKAGE.

====================================================================== | DEODORIZING PROCEDURE | WIRING | RELAY | A/C DELAYED | REMOVE | | DIAGRAM | | CONTROL PKG | BLOWER | ALTERNATIVE | | | VEHICLES | RESISTOR| PROCEDURE | FIGURE # | REQUIRED |NOT REQUIRED ======================================================================

A CAR X 5 B CAR X 6,7 C CAR X 8,9,10,11,12 D CAR X 13,14 E CAR X (A) 15 *(B) F CAR FIG. 1,2 16 G CAR X 17 H CAR X 9,10,11,12 J CAR X 18,19 X(C) K CAR X (A) 15 *(B) K SPECIAL (A) *(B) L CAR X 20 N CAR X 21 U VAN X 22 V CAR X 23 W CAR X 24 Y CAR 25 C/K TRUCK FIG. 3 26,27 X S/T TRUCK X 28 M/L VAN FIG. 4 28 G VAN (1995) X 28

IMPORTANT:

(A) 1996 ONLY (USE BLOWER RESISTOR LOCATION FOR DRILLING PROCEDURE) (B) 1994-1996 ONLY * REFER TO APPROPRIATE SERVICE MANUAL FOR ENABLING AFTERBLOW FEATURE THROUGH ON-BOARD DIAGNOSTICS.

PARTS INFORMATION:

P/N =====

DEODORIZING AEROSOL KIT - 12377951 (AC 15-102) (INCLUDES INSTRUCTIONS)

A/C DELAYED BLOWER CONTROL PKG. - 12370470 (AC 15-8632) (INCLUDES INSTRUCTIONS, LABEL, CONNECTORS)

RELAY KIT - 12167112 (AC 15-8264) (INCLUDES CONNECTOR WITH LEADS)

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION LABOR NUMBER DESCRIPTION TIME ========= =========== =====

D3316 DEODORIZE/INSTALL DELAYED 1.2 HR BLOWER CONTROL PKG.

CADILLAC ONLY:

D3319 CLEAN/DEODORIZE .3 HR D3318 INSTALL BLOWER CONTROL PACKAGE .4 HR D3317 ENABLE AFTERBLOW MODE .2 HR (E,K,K SPECIAL, 1994-96 ONLY)

FIGURES: 28 ATTACHMENTS: 00

FIGURE 1: 1. BLOWER MOTOR 2. HVAC MODULE 3. TEMPLATE (SHOWN IN PLACE)

FIGURE 2: 1. CUT TEMPLATE ALONG DOTTED LINE AND TAPE TO BLOWER MOTOR HOUSING. 2. DRILL 3.0MM (1/8 INCH) HOLE WITHIN CROSS SECTION AREA.

FIGURE 3: 1. DRILL A 3.0MM (1/8") HOLE.

FIGURE 4: 1. DRILL A 3.0MM (1/8") HOLE.

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 1996 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.