Blower Motor: Description and Operation

System Operation

Blower motor speed is controlled by the blower switch and a resistor in the blower unit. When the blower switch is in the OFF position, the motor ground circuit is open and the blower motor does not operate. When the switch is in the first position, current flow from the blower motor is restricted by the resistor, and the blower motor turns at low speed.

Changing the blower switch to the second, third, or fourth positions causes the circuit resistance to decrease and the blower speed to increase.