A/C Signal: Description and Operation
PURPOSEPowertrain 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.