REDUCED A/C PERFORMANCE IN HIGH AMBIENT TEMP. & HUMIDITY

VEHICLES AFFECTED: 1988 W-CAR W/2.8L Enqlne

The following are conditions that have been identified as the probable causes and their solutions in addressing customer comments of reduced A/C performance on all W-cars with 2.8L engines and single cooling fan.

Reduced A/C Performance At Idle Or Low Speeds In City Traffic ------------------------------------------------------------- This condition may be caused by reduced air flow across the condenser due to the cooling fan not being on all the time. This can be addressed by disconnecting the electrical connector to the cooling fan intermediate pressure switch. This switch is located in the high pressure line from evaporator to condenser, as shown in Figure 1. Tape the connector back on the harness making sure that the tape seals the opening of the connector, DO NOT REMOVE OR REPLACE THE SWITCH. Disconnecting this switch will allow the cooling fan to run all the time when the A/C is on and improve the air flow across the condenser.

Overcharged A/C System ---------------------- Refrigerant overcharge can be a contributing factor to the reduced performance of the A/C system. This, however, should be verified by doing an A/C Performance Check, Bulletin # 88-1-143.

If the A/C temperature and pressure reading are not within the upper limits shown on the Performance Chart, the system refrigerant charge should be suspect.

Discharge, evacuate and refill the system with 2.25 lbs. of refrigerant, per the label on the left front shock tower.

The A/C system should then be rechecked for performance.

Delayed A/C Cooling After Engine Start Up ----------------------------------------- Some vehicles may exhibit a slow to stroke V5 compressor causing a delay in the cooling of the A/C system. This condition can be addressed by using the procedure in Bulletin # 88-1-105 for Delay A/C Cooling.

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.