A/C - Temporary Loss of A/C in High Ambient Temperatures

File In Section: 1 - HVAC

Bulletin No.: 63-12-13

Date: September, 1996

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 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 RP0 C34 (rear A/C) and for vehicles with RP0 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

Switch Kit, A/C
15981985 Compressor High 1
Pressure Cut-off

15987428 Fitting, A/C Evaporator 1
Tube

Parts are currently available from GMSP0.

Warranty Information

For vehicles repaired under warranty, use:

Labor
Operation Description Labor Time

Switch, Compressor Use published
D1116 Cut-off - Replace labor operation
time

Relocate
Add Compressor High 0.1 hr
Pressure Cut-off
Switch