A/C Signal: Description and Operation

PURPOSE

Powertrain Control Module (PCM) monitors engine load and A/C system pressure, and cycles the A/C compressor clutch accordingly.

CONDITIONS

A/C or Defrost switch ON.

Combination valve, A/C low pressure and high pressure switches are closed.

OPERATION

Powertrain Control Module (PCM) receives an A/C selected signal.

- PCM engages A/C compressor clutch (by grounding clutch relay).

- PCM cycles compressor clutch depending on engine load and A/C system pressure.

- PCM maintains correct engine idle speed, through the Idle Air Control (IAC) Motor.