BLOWN FUSE, ERRATIC HVAC OPERATION (INSULATE WIRES). GMC Truck GMC Suburban

SUBJECT: BLOWN FUSE, ERRATIC HVAC OPERATION, AND SELF DIAGNOSTIC FEATURE BLINKS (INSULATE WIRES)

MODELS: 1994 AND PRIOR CHEVROLET AND GMC C/K TRUCKS

CONDITION:

SOME OWNERS MAY EXPERIENCE A BLOWN FUSE, ERRATIC HVAC OPERATION, OR A BLINKING HVAC CONTROL HEAD SELF DIAGNOSTIC INDICATOR.

CAUSE:

TWO POSSIBLE HARD TO FIND CAUSES HAVE BEEN DISCOVERED FOR THE ABOVE SYMPTOMS:

- SIX WAY I/P TO HVAC CONNECTOR TERMINALS MAY SHORT TO THE ASHTRAY. THE CONNECTOR HAS SLOTS TO ACCOMMODATE THE TERMINAL POSITIVE ATTACHMENT LOCKS THAT ALLOW METAL TO METAL CONTACT BETWEEN THE EXPOSED TERMINALS AND THE ASHTRAY (FIGURE 1).

- THE HVAC HARNESS FROM THE CONTROL HEAD TO THE BLOWER AND MODE DOOR MOTORS, RUNNING ACROSS THE VEHICLE JUST UNDER THE DASH PANEL, MAY CHAFE AGAINST THE CASSETTE DECK SUPPORT BRACKET (FIGURE 2).

CORRECTION:

BOTH CONDITIONS CAN BE CORRECTED BY TAPING OR OTHERWISE SHIELDING THE WIRES FROM CONTACT WITH THE RESPECTIVE METAL EDGES. IF THE SECOND CONDITION HAS CAUSED SIGNIFICANT WIRE DAMAGE, REPAIR ACCORDING TO GUIDELINES FOUND IN THE WIRE REPAIR SECTION OF THE APPROPRIATE SERVICE MANUAL.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME

N6030 WIRING AND/OR CONNECTOR REPAIR, A/C USE PUBLISHED LABOR OPERATION TIME

FIGURES: 2

CAPTIONS: FIGURE 1 - I/P TO HVAC CONNECTOR FIGURE 2 - HVAC HARNESS ROUTED UNDER CASSETTE DECK SUPPORT BRACKET

Object Number: 83032 Size: FS

Object Number: 83031 Size: FS

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.