Component Diagnostic Charts/Tests

Fig. 030 CHART C-10 A/C CLUTCH CONTROL:

Fig. 030 WIRING DIAGRAM CHART C-10 A/C CLUTCH CONTROL:

ECM control of A/C improves idle quality by:
1. Delaying clutch until idle air rate is increased.
2. Turning off clutch if idle speed is too low.
3. Turning off clutch at wide open throttle.
4. Allows smooth cycling by providing more fuel when the clutch is applied.

Voltage is supplied to control relay on CKT 50 as the A/C power relay is energized by the control switch. At the same time voltage is supplied to the A/C relay coil on CKT 67 and as a signal to ECM terminal 21. After 1/2 second the ECM grounds terminal 7 (CKT 458) and closes the A/C relay.

When the relay is energized battery voltage from CKT 50 is supplied to the A/C clutch through the relay and CKT 59.