Chart C-10, 3.1L (1 Of 2), A/C Clutch Control CKT Diagnosis: Notes

A/C relay is ECM controlled to delay A/C clutch engagement .4 second after A/C is turned on. This allows IAC to adjust engine RPM for additional load.

The ECM 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) and TPS angle at 90 percent.
Power steering pressure high (open PSPS).
Engine speed greater than 6000 RPM.
During IAC reset.

The A/C clutch is energized when ECM provides a ground path for circuit No. 459. The A/C pressure sensor is used to determine high and low pressure in the system and also turns on the cooling fan, when needed.

NOTE: Test numbers refer to test numbers on diagnostic charts.

ECM will only energize A/C relay when engine is running. This test will determine if relay or circuit No. 459 is faulty.
This test determines if signal is reaching ECM on circuit No. 66 from A/C control panel. Signal should only be present when A/C or defrost mode has been selected.
If ECM sees a high power steering pressure signal, ECM will disengage A/C clutch.