Test K: The A/C Does Not Operate/Does Not Operate Correctly

PINPOINT TEST K: THE A/C DOES NOT OPERATE/DOES NOT OPERATE CORRECTLY

K1-K3:

K3-K7:

K7-K10:

K10-K12:

K13-K15:

K16-K18:

K19-K21:

K22-K24:

K24-K26:

Normal Operation
Under normal operation, when A/C is requested, a message is sent over the bus to the PCM (DATC systems) or sends voltage to the PCM through circuit 348 (VT) (manual climate control systems). The PCM receives input from the A/C cycling switch through circuit 347 (BK/YE) and from the A/C pressure cutoff switch through circuit 441 (RD/YE). Ground is provided to the A/C cycling switch and A/C pressure cutoff switch through circuit 570 (BK/WH).

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 1139 (VT/YE). Ignition voltage for the A/C clutch relay switch is provided through circuit 1003 (GY/WH). 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 1205 (BK).

Possible Causes
- An open in circuits 441 (RD/YE), 348 (VT), 1139 (VT/YE), 570 (BK/WH), 347 (BK/YE), 1205 (BK), 1003 (GY/WH), 321 (GY/WH) or 331 (PK/YE).
- A short to voltage in circuit 348 (VT) or 331 (PK/YE).
- A short to ground in circuit 347 (BK/YE) or 441 (RD/YE).
- PCM.
- (DATC systems) DATC module.
- (Manual climate control systems) Function selector switch.
- A/C cycling switch.
- A/C pressure cutoff switch.
- A/C compressor clutch field coil.
- A/C control relay.
- A/C clutch air gap.