Chart C-10A A/C Clutch Control (Part 1 of 2)

CIRCUIT DESCRIPTION
The A/C clutch control relay is Engine Control Module (ECM) controlled to delay A/C clutch engagement 0.4 seconds after A/C is turned on. This allows the IAC to adjust engine RPM before the A/C clutch engages. The ECM also causes the relay to disengage the A/C clutch during WOT, when high power steering pressure is present, or if engine is overheating. The A/C clutch control relay is energized when the ECM provides a ground path for CKT 905.

CHART TEST DESCRIPTION
1. Checks to see if ECM is controlling A/C clutch control relay.

2. Checks operation of A/C cycling switch.

3. Checks for grounded CKT 905 to ECM. At this point the test light should be off.

4. If the ECM recognizes a high power steering pressure the A/C clutch relay will be deenergized. The ECM will pulse CKT 905 on and off to de-energize the relay. This would cause a blinking test light when CKT 905 was tested.