For 1990-2009 cars

# INFORMATION TO CLARIFY THE HVAC SYSTEM CONTENT

#### SUBJECT: INFORMATION TO CLARIFY THE U VAN REAR HVAC SYSTEM CONTENT

#### MODELS: 1990-94 CHEVROLET LUMINA APV 1990-94 PONTIAC TRANS SPORT 1990-94 OLDSMOBILE SILHOUETTE

BASED ON CUSTOMER AND DEALER QUESTIONS WE RECEIVE, THERE APPEARS TO BE CONSIDERABLE CONFUSION REGARDING THE CONTENT AND APPLICATION OF OPTION CODES C34 (REAR HEATER AND AIR CONDITIONER) AND C36 (REAR HEATER). THIS CONFUSION STEMS FROM THE FACT THAT THESE SYSTEMS HAVE IDENTICAL DUCTWORK AND CONTROLS TO MINIMIZE PARTS PROLIFERATION.

"C34" REAR HEATING AND AIR CONDITIONING:

THIS SYSTEM IS OPTIONAL (BUT NOT REQUIRED) ON ALL VEHICLES WITH FRONT A/C (C67). IT IS CAPABLE OF PROVIDING HEATED AIR TO THE FLOOR AND SIDE WINDOWS. IT IS CAPABLE OF PROVIDING COOLED AIR THROUGH THE OVERHEAD OUTLETS AND THE THIRD ROW SIDE OUTLET. THE DISTRIBUTION MODE AUTOMATICALLY PARALLELS THE MODE SELECTED ON THE FRONT UNIT BUT WITH SEPARATE FAN CONTROL. SEE DIAGRAM 1.

"C36" REAR HEATER ONLY: (CANADIAN VEHICLES ONLY)

THIS SYSTEM IS NOW BASE EQUIPMENT ON ALL CANADIAN VEHICLES WITH 7 PASSENGER SEATING. IT WAS DEVELOPED TO PROVIDE REAR HEAT WITHOUT THE ADDITIONAL COST OF REAR A/C, WHICH MANY CANADIAN CUSTOMERS FIND UNNECESSARY. IT IS CAPABLE OF PROVIDING HEATED AIR TO THE FLOOR AND REAR SIDE WINDOWS. IT IS CAPABLE OF PROVIDING RECIRCULATED AIR ONLY (NOT HEATED OR COOLED) THROUGH THE OVERHEAD OUTLETS AND THE THIRD ROW SIDE OUTLET. THE DISTRIBUTION MODE AUTOMATICALLY PARALLELS THE MODE SELECTED ON THE FRONT UNIT BUT WITH SEPARATE FAN CONTROL. (C36 IS IDENTICAL TO C34 EXCEPT FOR THE REMOVAL OF THE REAR A/C EVAPORATOR.) SEE DIAGRAM 2.

THE BEST WAY TO CONFIRM THE CONTENT IN A SPECIFIC VEHICLE IS TO CHECK THE "SPID" LABEL ON THE GLOVE BOX DOOR.

PLEASE SHARE THIS INFORMATION WITH YOUR SALES DEPARTMENT.

FIGURES: 2

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 1994 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.