Blower Motor Resistor: Description and Operation

The blower resistor assembly is used in combination with the blower switch to determine blower speed. The blower resistor assembly 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.