Operation CHARM: Car repair manuals for everyone.

Control Module HVAC: Description and Operation

BLOWER SPEED CONTROLLER

The blower speed controller is located in the evaporator case, upstream of the evaporator core. The high blower relay is located on the upper half of the evaporator case. The relay converts low current signals from the control assembly to a high current, variable ground feed to the blower motor. The infinitely variable blower motor speed is controlled by the control assembly, as well as the position of the blend door actuator. A delay function allows a gradual increase or decrease in blower motor speed under all conditions.