Control Module HVAC: Description and Operation
Circuit DescriptionA/C control
With the ignition switch in ON, battery voltage is applied to the coil of the blower relay from fuse 16. With the blower switch in any position except OFF, ground is provided to the coil of the blower relay through the blower switch. Battery voltage is then applied to the A/C switch through the closed contacts of the blower relay and A/C fuse 2. With the A/C switch in ON, the engine control module (ECM) will ground the coil of the A/C control relay after a short delay to adjust idle speed. Battery voltage will then be applied to the compressor clutch from A/C fusel and the closed contacts of the A/C relay to make the A/C compressor run.