Blower Motor: Description and Operation

When you turn the ignition switch to START with the transmission control lever in park or neutral, voltage is applied to the starter relay, and the relay energizes.

When you release the ignition switch to ON with the engine running, the relay de-energizes and voltage is applied from the alternator to the heater and A/C relay through the normally closed contacts of the starter relay. This energizes the heater and A/C relay, allowing voltage to be applied from FL-I (MAIN) fusible link to the blower motor through fuse C-19.

Turning on the blower switch then applies ground to the blower resistor. As the blower switch moves from OFF to position 4, resistors are bypassed. As the resistance to ground is decreased, blower speed increases. When the blower switch is in position 4, all of the resistors are bypassed and the blower motor runs at the highest speed.