GM Service Manual Online
For 1990-2009 cars only

The following six actuators control the automatic climate control system:

    • The electric air mix door actuator
    • 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 electric air mix door actuator contains a feedback potentiometer. The feedback potentiometer reports the position of the air mix door to the heater and A/C control module. If the air mix door actuator 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 RDO BATT fuse for 10 seconds.
  3. Reinstall the RDO BATT fuse.
  4. Turn the ignition switch to the ON position.
  5. Ensure that the air mix door actuator cycles through the hot and cold range.