Pinpoint Test 4: The Air Conditioning (A/C) Is Inoperative/Does Not Operate Correctly

PINPOINT TEST 4: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY

Normal Operation

Voltage is supplied to the A/C clutch cycling pressure switch through circuit (G/BR). When the A/C clutch cycling pressure switch is closed (ON), voltage is sent to the dual pressure switch through circuit (V). When the dual pressure switch is closed (ON), voltage is provided to the PCM. Ignition voltage is provided to the A/C clutch relay switch through circuit (GY/R). When A/C is requested, a message is sent over the MS-CAN bus to the PCM. When the PCM energizes the relay, ignition voltage is supplied to the A/C clutch through circuit (V/W). Ground is supplied for the A/C clutch through circuit (B/G).

Possible Causes
- Fuse(s)
- Wiring, terminals or connectors
- PCM
- Electronic manual temperature control (EMTC) module
- A/C clutch cycling pressure switch
- Dual pressure switch
- A/C compressor clutch field coil
- A/C clutch relay
- A/C clutch air gap
- Battery junction box (BJB)

Diagnostic Procedure

NOTE:Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. See - PCM - DTC Index.
NOTE:Before carrying out the following test, diagnose any instrument cluster DTCs.
NOTE:When disconnecting and reconnecting the pressure transducer electrical connector, make sure that the connector-locking device is in place and that the locking device and connector are correctly and fully seated.
NOTE:Before carrying out the following test, check that the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), see Fluorescent Dye Leak Detection.