Control Assembly: Description and Operation

Blower motor speed is controlled by the blower switch and a resistor assembly 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 four resistors in the resistor assembly, and the blower motor runs at a low speed. Changing the blower switch to the second, third or fourth positions causes the circuit resistance to decrease, and the blower motor speed to become correspondingly faster.