X62 - Isolate Fault to PCM or CCRM

- Key "OFF".

- Breakout box installed, Powertrain Control Module (PCM) disconnected.

- Reconnect Constant Control Relay Module (CCRM) and A/C clutch.

- Key "ON", engine "OFF".

- A/C demand switch to "A/C" on position.

- Connect jumper between test pins 54 and 40 at the breakout box.

- Disconnect and reconnect jumper several times while listening to the A/C clutch.

- Does the A/C clutch engage and disengage as the jumper is disconnected and reconnected?

Yes -- For No A/C symptom: Remove jumper. Go to X63. X63 - Check ECT and TP Inputs

For No Wide Open Throttle A/C Cut-Off (WAC) symptom: Replace PCM. Remove breakout box. Reconnect all components. Re-evaluate symptom.

No -- Replace CCRM. Inspect the A/C clutch circuit for possible shorts to GND. Service as necessary. Remove breakout box. Reconnect all components. Re-evaluate symptom.