X155 - Check Dual Function A/C Pressure Switch

- Key "OFF".

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

- Constant Control Relay Module (CCRM) disconnected.

- Disconnect the dual function A/C Pressure Switch (ACPSW) (also known as the Refrigerant Containment/Fan Function Switch).

- Again, measure resistance between test pin 31 and test pin 40 at the breakout box.

- Is resistance now greater than 10,000 ohms?

Yes -- Go to the Heating and Air Conditioning to check ACPSW operation.

No -- Service short to ground in High Fan Control (HFC) circuit. Remove breakout box. Reconnect all components. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)