TEMPORARY LOSS OF A/C IN HIGH AMBIENT TEMPERATURES. Pontiac Trans Sport 1994

SUBJECT: TEMPORARY LOSS OF A/C IN HIGH AMBIENT TEMPERATURES (RELOCATE HIGH SIDE CUT-OFF SWITCH)

MODELS: 1993-95 CHEVROLET LUMINA APV 1993-95 OLDSMOBILE SILHOUETTE 1993-95 PONTIAC TRANS SPORT WITH 3.8L ENGINE (VIN L - RPO L27)

CONDITION:

SOME OWNERS MAY COMMENT ON TEMPORARY LOSS OF A/C IN STOP AND GO CONDITIONS WITH HIGH AMBIENT TEMPERATURES.

CAUSE:

HIGH AMBIENT TEMPERATURES, ALONG WITH THE RE-CIRCULATION OF UNDER HOOD TEMPERATURES THROUGH THE A/C CONDENSER, COULD RESULT IN A PRESSURE SPIKE IN THE A/C SYSTEM. THIS PRESSURE SPIKE WILL SIGNAL THE HIGH SIDE CUT-OFF SWITCH TO SHUT DOWN THE COMPRESSOR UNTIL THE SWITCH REINITIALIZES. THIS CONDITION WILL LEAVE THE CUSTOMER TEMPORARILY WITHOUT AIR CONDITIONING.

CORRECTION:

TO CORRECT THIS CONDITION, THE HIGH SIDE CUT-OFF SWITCH MUST BE RELOCATED FORWARD OF THE HIGH SIDE SERVICE CHARGE PORT USING THE A/C EVAPORATOR TUBE FITTING (SADDLE CLAMP), P/N 15987428, AND A/C COMPRESSOR HIGH PRESSURE CUT-OFF SWITCH KIT, P/N 15981985.

PROCEDURE:

1. RECOVER REFRIGERANT, REFER TO "REFRIGERANT RECOVERY" IN SECTION 1B OF THE SERVICE MANUAL.

2. LOCATE A STRAIGHT, CLEAN AND ROUND SECTION OF PIPE FORWARD OF THE HIGH SIDE SERVICE CHARGE PORT WHERE THE SADDLE CLAMP CAN BE INSTALLED. FOLLOW THE DETAILED INSTRUCTIONS INCLUDED IN THE SADDLE CLAMP KIT USING LOCTITE(R) 242, OR EQUIVALENT, AND PROPERLY TORQUE SCREWS TO THE SPECIFICATION IDENTIFIED IN THE INSTRUCTIONS.

3. ATTACH NEW HIGH PRESSURE CUT-OFF SWITCH WITH O-RING AND CONNECT NEW WIRING HARNESS. ROUTE WIRES ON HARNESS TOWARD OLD HIGH PRESSURE SWITCH LOCATED AT REAR OF A/C COMPRESSOR AND SECURE. DISCONNECT WIRING AT OLD HIGH PRESSURE SWITCH AND CUT OFF CONNECTOR. SPLICE THE NEW WIRES TO THE EXISTING WIRES USING THE CONNECTORS SUPPLIED IN THE KIT.

4. EVACUATE AND RECHARGE SYSTEM TO 2.25 LB (1.02 KG) WITHOUT RPO C34 (REAR A/C) AND FOR VEHICLES WITH RPO C34 (REAR A/C), REFERENCE CORPORATE BULLETIN NUMBER 63-12-07 OR CHARGE TO 3.25 LB (1.46 KG).

5. CHECK SYSTEM FOR LEAKS. REFER TO "LEAK TESTING" IN SECTION 1B OF THE SERVICE MANUAL.

PARTS INFORMATION:

P/N DESCRIPTION QUANTITY === =========== ========

15981985 SWITCH KIT, A/C COMPRESSOR HIGH 1 PRESSURE CUT-OFF

15987428 FITTING, A/C EVAPORATOR TUBE 1

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

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

D1116 SWITCH, COMPRESSOR CUT-OFF - USE PUBLISHED REPLACE LABOR OPERATION TIME

ADD: RELOCATE COMPRESSOR HIGH .1 HR PRESSURE CUT-OFF SWITCH

FIGURES: 00 ATTACHMENTS: 00

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.