Part 1 of 2

Chart C-10 - A/C Clutch Control Circuit Diagnosis:

A/C Clutch Control Wiring Circuit:

Circuit Description:

The A/C clutch control relay is energized when the Powertrain Control Module (PCM) provides a ground path through CKT 459 and A/C is requested. A/C clutch is delayed about .3 second after A/C is requested. This will allow the IAC valve to adjust engine RPM for the additional load.

The PCM will temporarily disengage the A/C clutch relay for calibrated times for one or more of the following:
^ Hot engine restart.
^ Wide Open Throttle (WOT) (TP sensor over 90%).
^ Engine RPM greater than about 6000 RPM.
^ During IAC valve reset.

The A/C clutch relay will remain disengaged when DTC 66 is present, if A/C refrigerant pressure is out of range as described previously in this section, or there is no A/C request signal due to an open A/C select switch or circuit.

Chart Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.
1. The PCM will only energize the A/C relay when the engine is running. This test will determine if the relay or CKT 459 is faulty.
2. Determines if the signal is reaching the PCM through CKT 66 from the A/C control panel. Signal should only be present when an A/C mode or defrost mode has been selected.