A/C Clutch: Notes

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

On many models, PCM regulates operation of the A/C clutch through an PCM-controlled relay. The PCM disengages the A/C compressor when compressor load on engine may cause driveability problems (i.e., during hot restart, idle, low speed steering maneuvers and wide open throttle operation) or if A/C refrigerant pressure drops to less than or rises to greater than normal operating levels.

Refrigerant pressure is sensed through the monitoring of high and low pressure switches or a pressure sensor which registers either high or low pressure levels. Power steering load is monitored through a power steering pressure switch (2.5L). Hot restart is monitored through the coolant temperature sensor. For component application and related wiring, see wiring schematics under MISCELLANEOUS PCM CONTROLS in SYSTEM/COMPONENT TESTS - GASOLINE article in the ENGINE PERFORMANCE section.