Test J: The Air Conditioning (A/C) Is Always On
PINPOINT TEST J: THE AIR CONDITIONING (A/C) IS ALWAYS ONNormal Operation
Under normal operation, when A/C is requested, a message is sent over the UART-based protocol (UBP) bus to the instrument cluster, then from the instrument cluster through the controller area network (CAN) bus to the PCM (HVAC module - electronic automatic temperature control [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 (HVAC module - electronic manual temperature control [EMTC] systems). Voltage is provided to the A/C cycling switch through circuit 295 (LB/PK). The PCM receives input from the A/C cycling switch 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 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).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM
- HVAC module - EATC
- HVAC module - EMTC
- A/C compressor clutch field coil
- A/C control relay
- A/C clutch air gap
J1-J5:
J5-J8:
