A/C Clutch

On many models ECM regulates operation of the A/C clutch through an ECM controlled relay. This allows the ECM to disengage 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 freon pressure drops below or rises above normal operating levels. Freon pressure sensing may be accomplished through the monitoring of high and low pressure switches or a pressure sensor which will register either high or low pressure levels. Power steering load is monitored through a power steering pressure switch. Hot restart is monitored through the coolant temperature sensor. For component application and related wiring, see wiring schematics in MISCELLANEOUS ECM CONTROLS in SYSTEM/COMP TESTS article.