Battery voltage is supplied to the blower motor resistor relay assembly connector at all times. When the ignition switch is OFF or the blower switch is in any position except HI, no voltage is applied to the relay coil via blower high speed and the relay remains de-energized.

With the blower switch in HI, the blower resistors are bypassed and voltage is supplied to the coil side of the permanently grounded relay. This closes the contacts and supplies full battery voltage from the engine wiring harness junction block to the blower motor which will operate at the highest speed.

When the blower switch is in LO to any MEDIUM speed, voltage is reduced through the appropriate resistors which will limit the blower speed accordingly.

The blower motor resistor relay assembly is located next to blower motor under right side of glove compartment (Pickup) or at the right rear module assembly (Utilities w/auxiliary A/C).