Chart C-10 A/C Clutch Control Circuit Diagnosis

Chart C-10:

Wiring Diagram For A/C Clutch Circuit:

CIRCUIT DESCRIPTION:

When the Electronic Climate Control (ECC) head is switched to the "ON" position, and the A/C system has an adequate charge, an A/C request signal is sent to the ECM. When the A/C request signal is received by the ECM, the ECM will delay grounding relay circuit 459 long enough to adjust the engine idle speed. Once the idle speed has been adjusted, the ECM will remove the ground from the relay circuit 459. This will allow current to flow through the relay and to the A/C compressor clutch. The ECM will also disable the A/C clutch relay during Wide Open Throttle (WOT).


TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. This checks the A/C fuse for being open.
2. This checks to see if the ECM is controlling the A/C clutch control relay.
3. This checks for a grounded 459 circuit to the ECM.