Blower Motor Power Module - Operation

OPERATION

A blower motor power module is used on the Automatic Temperature Control (ATC) system, and allows the microprocessor-based A/C heater control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming.

The ATC blower motor control system uses a Pulse Width Modulated (PWM) circuit strategy. 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 is diagnosed using a scan tool A L L Diagnostic Trouble Codes ( DTC ).

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