Module-Power-Blower Motor: Operation

WARNING: This page is about a different car, the 2006 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

The blower motor power module is connected to the vehicle electrical system through a dedicated lead and connector of the HVAC wire harness. A second connector receptacle receives the wire harness connector from the blower motor. The 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 blower motor feedback voltage. The resulting output drives the power module circuitry, which provides a linear output voltage to change or maintain the desired blower speed.

The blower motor power module can be diagnosed using a scan tool.

The blower motor power module cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.