Test J

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

Test J1-J3:

Test J3-J6:

Test J6-J8:

Test J8-J9:

Normal Operation
Under normal operation, when A/C is requested, a message is sent over the UBP bus to the instrument cluster, then from the instrument cluster through the CAN bus to the PCM (EATC systems) or sends voltage to the instrument cluster through circuit 348 (VT) then a message from the instrument cluster through the CAN bus to the PCM (EMTC systems). Voltage is provided to the A/C pressure cutoff switch through circuit 295 (LB/PK). The PCM receives input from the A/C pressure cutoff switch through circuit 441 (RD/YE) and through the A/C cycling switch to 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 391 (RD/YE). Ignition voltage for the A/C clutch relay switch is provided through circuit 883 (PK/LB). When the relay is activated, ignition 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).

Possible Causes
- An open in circuit 331 (PK/YE).
- A short to voltage in circuit 321 (GY/WH), 348 (VT) or 331 (PK/YE).
- A short to ground in circuit 331 (PK/YE).
- PCM.
- (EATC systems) EATC module.
- (Manual climate control systems) Manual climate control module.
- A/C compressor clutch field coil.
- A/C control relay.
- A/C clutch air gap.