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Power Module: Notes

Power module controls operation of compressor clutch and blower motor. It is located on top of evaporator assembly in HVAC air stream. See Fig 1 . Power module receives blower drive signal from programmer and amplifies signal to a strong output voltage proportional to input. Power module is also transistorized, and can provide variable blower speeds. Power module also receives a drive signal from ECM, which is used to engage A/C compressor clutch. BCM controls cycling of clutch based upon its inputs.

Fig 1: Locating Power Module & Blower Motor
G00080762Courtesy of GENERAL MOTORS CORP.