Through Model Year 2010

Front Blower Motor Power Module

Description






A blower motor power module is used on this model when equipped with the automatic temperature control HVAC system. Models equipped with the manual temperature control HVAC system use a blower motor resistor block, instead of the blower motor power module. Refer to => [ Front Blower Motor Resistor ] Description and Operation.

The front blower motor power module is mounted to the rear of the HVAC housing, on the passenger side of the vehicle. The blower motor power module consists of a molded plastic mounting plate (1) with two integral wire connector receptacles (3). Concealed behind the mounting plate is the power module electronic circuitry and a large finned heat sink (2).

The blower motor power module is accessed for service from underneath the instrument panel.

Operation

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 HVAC 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 circuit strategy.

The PWM voltage is applied to a compressor 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 is diagnosed using a scan tool.

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