Description And Operation: Operation

The blower motor controls the velocity of air moving through the HVAC housing by spinning the blower wheel at the selected or programmed speed.

Both the Manual Temperature Control (MTC) and the Automatic Temperature Control (ATC) heating and A/C systems have an electronic blower motor power module, that is integral with the blower motor assembly, to control blower motor speed. The power module uses a Pulse Width Modulated (PWM) input from the HVAC module and a feedback signal from the blower motor to regulate the blower motor ground path. The blower motor power module is used on MTC and ATC HVAC system blower motors and allows the microprocessor-based HVAC module to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming. On both systems, the blower motor receives battery current through the Power Distribution Center (PDC) whenever the ignition switch is in the RUN position, and the blower motor control is in any position except OFF.

The blower motor control system is diagnosed using a scan tool. Refer to STANDARD PROCEDURE .

The blower motor, blower motor power module and blower motor wheel are factory balanced as an assembly and cannot be adjusted or repaired and must be replaced as a unit if inoperative or damaged.