A/C Signal: Description and Operation

On models equipped with air conditioning, the A/C signal informs the ECM that the A/C switch is turned "ON" and the A/C pressure cycling switch is closed. With this input, the ECM can improve engine idle quality and performance by:

1. Delaying A/C clutch apply until idle speed is raised.
2. Releasing clutch when idle speed is too low or during high power steering loads.
3. Releasing clutch at wide open throttle.
4. Smooth cycling of compressor by providing additional fuel at the instant of clutch application.