Operation CHARM: Car repair manuals for everyone.

Control Module HVAC: Description and Operation

Air Conditioning (A/C) Signal

PURPOSE
Informs the ECM when the A/C system is on.

OPERATION
This signal is sent from the air-conditioner circuit. The ECM detects whether the air-conditioner is operating or not through this signal, and uses it as one of the signals for controlling IAC valve operation.