Powertrain Control Module Controlled Air Conditioning. Cadillac Concours 1997

For 1990-2009 cars

### A/C System

A/C operation is requested by the 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. 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 (40°F)

• | Certain PCM DTCs set

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