Air Door Actuator / Motor: Description and Operation

Electronic Servomotor

The electronic servomotor is located on the evaporator-heater assembly above the blend-air door shaft. The servomotor measures the resistance of the sensors and the control head resistor and moves the blend-air door to a position which corresponds to a certain electrical resistance. High sensor or control head resistor resistances cause the servomotor to move the blend-air door to a higher (more heat) position.