Automatic Temperature Control (ATC) System

AUTOMATIC TEMPERATURE CONTROL (ATC) SYSTEM

The blower motor power module for the Automatic Temperature Control (ATC) heating-A/C system is connected to the vehicle electrical system through a dedicated lead and connector. A second lead and connector is connected to the blower motor. The blower motor power module allows the microprocessor-based 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 is diagnosed using a scan tool Testing and Inspection.

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