GM Service Manual Online
For 1990-2009 cars only
  1. Start the vehicle.
  2. Set the temperature to 32°C (90°F) at the heater and A/C control.
  3. Set the passenger temperature control to full warm.
  4. Refer to the following list:

    • If the outside temperature is above 32°C (90°F), disconnect the inside temperature sensor.
    • Allow 45 seconds in order for the air mix valve actuators to move to the warm position.
  5. Gently pull the driver temperature valve link (11) toward the programmer (6) until the valve hits the stop.
  6. Push the threaded portion of the link into the slot of the driver temperature valve crank.