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

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

I1-I6:

I6-I8:

I9-I10:

I11-I13:

I13-I14:

I15-I17:

I17-I19:

I19-I21:

Normal Operation
Under normal electronic automatic temperature control (EATC) operation, when A/C is requested, a message is sent over the bus from the EATC module to the powertrain control module (PCM). The PCM receives input from the A/C cycling switch through circuit 883 (PK/LB). Voltage is provided to the A/C cycling switch through circuit 348 (RD/VT).

Under normal manual climate control operation, when A/C is requested the function selector switch sends voltage to the A/C cycling switch through circuit 348 (RD/VT). The PCM receives input from the A/C cycling switch through circuit 883 (PK/LB). Voltage is supplied to the function selector switch through circuit 1040 (RD/BK).

The PCM provides a ground for the A/C clutch relay coil through circuit 73 (OG/LB). 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 1810 (LG/OG). 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
- Fuse(s)
- An open in circuit 57 (BK), 73 (OG/LB), 321 (GY/WH), 391 (RD/YE), 348 (RD/VT), 883 (PK/LB) or 1810 (LG/OG)
- A/C pressure transducer
- PCM
- A/C control relay
- Function selector switch
- Electronic automatic temperature control (EATC) module
- A/C cycling switch
- A/C compressor clutch field coil
- A/C clutch air gap