Blower Motor: Description and Operation

Blower motor
Blower motor speed is controlled by the blower switch and a resistor assembly in the blower unit. When the blower switch in the OFF position, the motor ground circuit is open and the blower motor does not operate. When the switch is in the first (LO) position, current how to the blower motor is restricted by the three resistors in the resistor assembly, and the blower motor turns at a low speed. Changing the blower switch to the second (M1), third (M2), or fourth (HI) positions causes successive decreases of the circuit resistance, resulting in the blower motor speed becoming correspondingly faster.

Air mix actuator
When the temperature selector lever in the heater and A/C control panel is moved, a signal is sent to the actuator. The motor in the actuator assembly moves and its position is fed back to the temperature control module by means of a potentiometer. When the desired air mix door position is reached, the motor stops.