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

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

I1-I4:

I5-I8:

I9-I10:

I11-I13:

Normal Operation
Under normal operation, when A/C is requested, a message is sent over the MSCAN bus to the instrument cluster, then from the instrument cluster through the HSCAN bus to the PCM (EATC systems) or a voltage is sent to the instrument cluster through circuit 1424 (TN/BK) then a message from the instrument cluster through the HSCAN bus to the PCM (EMTC systems).

Ignition voltage for the A/C clutch relay switch is provided through circuit 3028 (DB/YE). When the PCM energizes the relay, ignition voltage is supplied to the A/C clutch through circuit 1810 (LG/OG). Ground is supplied for the A/C clutch through circuit 1205 (BK).

Possible Causes
- An open in circuits 1424 (TN/BK), 3028 (DB/YE), 1810 (LG/OG) or 1205 (BK)
- An short to voltage on circuit 1424 (TN/BK)
- PCM
- EATC module
- EMTC module
- A/C evaporator discharge temperature sensor
- A/C pressure transducer
- A/C compressor clutch field coil
- A/C control relay
- A/C clutch air gap