Rear Blower Motor Power Module - Operation

OPERATION

The rear blower motor power module is connected to the vehicle electrical system through a dedicated lead and connector of the rear HVAC wire harness. A second connector receptacle receives the wire harness connector from the rear blower motor. The rear blower motor power module allows the microprocessor-based automatic temperature control (ATC) A/C-heater control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming using a pulse width modulated (PWM) circuit strategy.


The PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the rear blower motor feedback voltage. The resulting output drives the power module circuitry, which adjusts the voltage output received from the rear blower motor relay to change or maintain the desired blower speed.


The rear blower motor power module is diagnosed using a DRBIII(R) scan tool.


The rear blower motor power module cannot be adjusted or repaired and must be replaced if found inoperative or damaged.