Front Blower Controls

Battery voltage is supplied at all times to High Blower Relay Cavity A2 through the RED (542) wire. When the Ignition Switch is OFF or the Blower Switch at the Heater Control Module or HVAC Control Module is OFF, no voltage is applied to the Relay Coil through the ORN (52) wire and the relay remains de-energized. Similarly, no voltage is applied to the normally closed contact at Cavity B2 of the relay. Battery voltage is not applied to the Blower Motor, and the motor does not operate at any speed.

When the Ignition Switch is in RUN and the Blower Switch is in LO, voltage is applied through all three Blower Resistors to the normally closed contact in the relay. The relay remains de-energized. Reduced voltage is applied to the Blower Motor through the PPL (65) wire and the motor operates at its slowest speed. With the Blower Switch in either M1 or M2, current flows through fewer resistors in the Blower Resistor and the Blower Motor runs faster.

With the Blower Switch in HI, the Blower Resistors are bypassed by the energizing of the High Blower Relay. The contacts change state and Battery voltage from the Underhood Fuse-Relay Center is applied directly to the Motor. The Blower Motor then operates at its fastest speed.