Blower Motor Resistor: Description and Operation

The blower resistor is used in combination with the blower switch to determine blower speed. The blower resistor consists of three resistors in the same housing: with the blower switch in LO, all three resistors are placed in the blower circuit and the blower motor runs at the lowest speed; with the blower switch in M1, two of the resistors are used and the blower motor runs faster; with the blower switch in M2, just one of the resistors is used and the blower motor runs even faster; with the blower switch in HI, none of the resistors are used and the blower motor runs at maximum speed.