Blower Motor: Operation

WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.

The blower motor controls the velocity of air moving through the HVAC housing by spinning the blower wheel within the HVAC air inlet housing at the selected speed or, in the automatic temperature control (ATC) system, at the selected or programmed speed.

Blower motor speed for the MTC system is controlled by regulating the blower motor ground path through the blower motor resistor and through the blower motor control located within the MTC A/C-heater control. The blower motor will operate whenever the ignition switch is in the Run position and the blower motor control in any position except Off.

For the ATC system, blower motor speed is controlled by the body control module (BCM). The BCM varies the duty cycle supplied by the blower motor power module to a fixed frequency output (pulse width modulation) as requested by the ATC blower motor control (manual mode) or by sensor data (automatic mode). The blower motor will operate whenever the ignition switch is in the Run position and the A/C-heater control power is turned on.

The blower motor and blower motor wheel are factory balanced and cannot be adjusted or repaired. If faulty or damaged, the blower motor and blower wheel must be replaced as an assembly.