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

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

Normal Operation
Under normal operation, voltage is provided to the function selector switch through circuit 498 (PK/BK). When A/C is requested, voltage is sent from the function selector switch to the A/C cycling switch through circuit 348 (VT). Voltage is sent from the A/C cycling switch to the dual-function pressure switch (diesel engine) or the A/C high pressure switch (gasoline engine) through circuit 441 (RD/YE). Voltage is sent from the dual-function pressure switch (diesel engine) or the A/C high pressure switch (gasoline engine) to the PCM through circuit 347 (BK/YE).

The PCM provides a ground for the A/C clutch relay coil through circuit 331 (PK/YE). The A/C clutch relay coil receives ignition voltage through circuit 361 (RD). Battery voltage for the A/C clutch relay switch is provided through circuit 932 (GY/WH). When the relay is energized, voltage is supplied to the A/C clutch solenoid through circuit 321 (GY/WH). Ground is supplied for the A/C clutch through circuit 57 (BK).

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM
- Function selector switch
- A/C control relay
- A/C clutch air gap

D1-D5:

D5-D6:

D6-D8:

D8 Continued: