A/C Signal: Description and Operation

PCM CONTROLLED AIR CONDITIONING
A/C operation is requested by the Air Conditioning Programmer (ACM) using a serial data (Class 2) message to the PCM. The PCM will ground the A/C relay allowing current to flow through the A/C Compressor clutch coil.

A/C INHIBIT MODE
The PCM will disable or inhibit A/C compressor clutch operation during the following conditions:

^ High power steering load indicated.

^ Engine not running.

^ Engine at wide open throttle.

^ Outside temperature below approximately 4°C (4O°F).

^ Certain PCM DTCs set.

COLD WEATHER ENGAGEMENT
The PCM will also engage the A/C compressor clutch during cranking in colder weather to prevent A/C slugging.