Chart C-1B A/C Solenoid Vacuum (SV) Valve Check

Chart C-1B:

A/C Amplifier Circuit:

CIRCUIT DESCRIPTION:
The A/C solenoid vacuum (SV) valve is located in the center engine compartment mounted to the bulkhead. When the A/C switch is turned "ON," the A/C amplifier grounds the A/C SV valve, allowing additional air to enter the intake manifold. With the increased air entering the intake manifold the engine idle speed is increased. At the same time, the Engine Control Module (ECM) receives a signal that the A/C system operation has been requested and that the idle speed has been adjusted. The ECM uses this signal to increase the fuel injector pulse width.

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

1. Checks to see if the engine idle speed increases with A/C operation.

2. Checks for an open in YEL or BLU/RED wire, a faulty A/C SV valve or for a faulty A/C amplifier.