Air Conditioning Switch: Description and Operation

PURPOSE
To send a signal to the Engine Control Module (ECM), activating the fast idle control system, with the A/C on.


OPERATION
When the dash mounted A/C switch is closed, the ECM activates the system by grounding the A/C relay.
Once the A/C system is activated, the ECM will increase the duty cycle of the Idle Air Control-Auxiliary Air Control (IACV-ACC) Valve and stabilize the idle.