Blower Motor Resistor: Description and Operation

Front Blower Motor Resistor:

This temperature control system uses a blower motor resistor. The blower motor resistor is mounted to the top of ventilation housing located in the engine compartment. The blower motor resistor consists of a molded plastic mounting plate with an integral retaining tab and wire connector receptacle. Concealed behind the mounting plate are coiled resistor wires contained within a ceramic heat sink.

The blower motor resistor is accessed for service without removing any other components.

The blower motor resistor block has multiple resistor wires. Each resistor wire changes the resistance in the blower motor current path to change the blower motor speed. The blower motor switch directs the current through the correct resistor wire to obtain the selected speed.

With the blower motor switch in the lowest speed position, voltage for the motor is applied through all of the resistor wires Each higher speed selected with the blower motor switch applies the blower motor current path through fewer of the resistor wires, increasing the blower motor speed When the blower motor switch is in the highest speed position, the blower motor resistor is bypassed and the blower motor circuit receives a direct path to battery voltage.

The blower motor resistor block cannot be repaired and, if faulty or damaged, it must be replaced.