GM Service Manual Online
For 1990-2009 cars only
  1. Start the engine.
  2. Set the temperature to 32°C (90°F).
  3. Allow a minimum of 45 seconds for the air mix door actuator (3) to move the output crank to the full hot position.
  4. Move the temperature door to the full hot position.

  5. Object Number: 305037  Size: SH
  6. Pull the door link from the retainer on the temperature door.
  7. Snap the door link into the retainer on the temperature door.