GM Service Manual Online
For 1990-2009 cars only

The following six actuators control the automatic climate control system:

    • The air temperature valve sensor and motor
    • The vacuum inlet door actuator
    • Four vacuum mode door actuators

When servicing an actuator, replace parts with the correct service parts for the actuator being serviced.

The air temperature valve sensor and motor contains a feedback potentiometer. The feedback potentiometer reports the position of the air temperature valve sensor and motor to the electronic climate control (ECC) module. If the air temperature valve sensor and motor has been removed or replaced for service the actuator must be initialized. Perform the following procedure in order to initialize the actuator:

  1. Turn the ignition switch to the OFF position.
  2. Remove the RADIO fuse for 10 seconds.
  3. Reinstall the RADIO fuse.
  4. Turn the ignition switch to the ON position.
  5. Ensure that the air temperature valve sensor and motor cycles through the hot and cold range.