Operation CHARM: Car repair manuals for everyone.

A/C Request Signal

OPERATION
This signal tells the Powertrain Control Module (PCM) the A/C selector switch is turned "ON," and that the A/C refrigerant pressure switch is closed.

The PCM uses this to adjust idle speed before turning "ON" the A/C clutch. If this signal is not available to the PCM, the A/C compressor will be inoperative.