Late Models

The air conditioning system uses an Air Conditioning Control Module (ACM) for Engine Controller input. When the operator makes an air conditioning selection, the ACM sends a signal to the Engine Controller.

The ACM controls the operation of the compressor clutch. The ACM will send a predict signal to the Engine Controller approximately 0.5 seconds before clutch activation. This allows the Engine Controller to increase the idle speed for the increase in engine load. The predict signal is sent continuously until the operator turns OFF the air conditioning compressor. When the signal to the Engine Controller stops, the ACM waits approximately 0.5 seconds, allowing the Engine Controller to drop the idle speed. After the delay, the compressor clutch is DE-ENERGIZED.