Test D: The Air Conditioning (A/C) Is Always On

PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS ALWAYS ON

D1-D4:

D4-D7:

D7-D9:

D9 Continued:

NOTE: Before carrying out the following test, diagnose any PCM DTCs.

Normal Operation
Under normal operation, the function selector switch is supplied voltage through circuit 1003 (GY/YE). When any mode requiring A/C is selected, the function selector switch sends voltage to the powertrain control module (PCM) through circuit 348 (VT). Ground is provided to the A/C high pressure switch through circuit 570 (BK/WH). Ground is supplied from the A/C high pressure switch to the A/C cycling switch through circuit 441 (RD/YE). The ground is then supplied from the A/C cycling switch to the PCM through circuit 347 (BK/YE).

Voltage is supplied to the A/C clutch relay switch through circuit 883 (PK/LB). When the relay is energized, voltage is sent to the A/C clutch through circuit 321 (GY/WH). The A/C clutch is grounded through circuit 57 (BK).

Possible Causes
- A short to voltage in circuits 321 (GY/WH) or 348 (VT)
- A short to ground in circuits 347 (BK/YE) or 441 (RD/YE)
- PCM
- Function selector switch
- A/C cycling switch
- A/C high pressure switch
- A/C control relay
- A/C clutch air gap