Power Module: Operation

WARNING: This page is about a different car, the 2004 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.

The blower power module is connected to the vehicle electrical system through a dedicated lead and connector from the instrument panel wire harness. A second connector receptacle receives a wire lead connector from the blower motor. The blower power module allows the microprocessor-based Automatic Temperature Control (ATC) heater-A/C control module to calculate and provide infinitely variable blower motor speeds based upon ATC programming which uses a Pulse Width Modulated (PWM) circuit strategy. The PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the blower motor feedback voltage. The resulting output drives the power module circuitry, which adjusts the voltage output received from the blower motor relay to change or maintain the desired blower speed. The blower power module is diagnosed using a DRBIII(R) scan tool. DIAGNOSIS AND TESTING .