Electronic Automatic Temperature Control

A/C Electronic Blend Door Actuator
The A/C electronic blend door actuator is located on the rear of the A/C evaporator housing.
- Its function is to move the air temperature blend doors on command from the control assembly.
- The A/C electronic blend door actuator contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the air temperature blend door.
- A 5 volt signal is applied to the ends of the potentiometer. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the electronic automatic temperature control module and is matched with the wiper voltage of the module potentiometer. The control module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the control module wiper voltage.

Vacuum Control Motors
The vacuum control motors:
- are located on the A/C evaporator housing, A/C recirculating air duct and heater air plenum chamber.
- direct system airflow to the vehicle interior as determined by the electronic automatic temperature control module or manual override.