Blower Motor: Description and Operation

When the ignition switch is in RUN, voltage is applied to the blower motor from fuse 25. The blower motor ground path is completed when you turn on the blower switch. In positions 1, 2 and 3, the ground path includes one or more of the blower resistors. As you move the switch from position 1 to position 3, resistors are bypassed. Decreasing the resistance will increase the voltage across the blower motor, increasing its speed. When the blower switch is in position 4, all of the resistors are bypassed and the blower motor runs at full speed.