GM Service Manual Online
For 1990-2009 cars only

The heating, cooling, and ventilation of the vehicle can be controlled with this system.


Object Number: 2042280  Size: G3
  1. Temperature Control

  2. Fan Control

  3. Air Delivery Mode Control

  4. Air Conditioning

  5. Recirculation

  6. Rear Window Defogger

(Off): Turn the fan control to this position to turn the fan off. Air still enters the vehicle and increases with vehicle speed depending on the mode and temperature settings. Turn on the recirculation mode to stop this airflow.

Temperature Control: Turn clockwise or counterclockwise to increase or decrease the temperature of the air in the vehicle.

(Fan Control): Turn clockwise or counterclockwise to increase or decrease the fan speed.

Air Delivery Mode Control: Turn clockwise or counterclockwise to change the direction of the airflow in the vehicle. The airflow can be set between modes. To change the current mode, select one of the following:

(Vent): Air is directed to the instrument panel outlets.

(Bi-Level): Air is directed to the instrument panel outlets, and the remaining air to the floor outlets and the defroster and side window outlets. Cooler air is directed to the upper outlets and warmer air to the floor outlets.

(Floor): Air is directed to the floor outlets, side window outlets, and defroster. Recirculation is not available in this mode.

(Floor/Defog): This mode clears the windows of fog and moisture. Air is directed to the windshield, side window, and floor outlets. The system runs the air conditioning unless the outside temperature is near freezing or below. Recirculation is not available in this mode.

(Defrost): This mode clears the windshield of fog or frost more quickly. Air is directed to the windshield and side window outlets. The system runs the air conditioning system unless the outside temperature is near or below freezing. Recirculation is not available in this mode. Do not drive the vehicle until all the windows are clear.

(Air Conditioning): Press to turn the air conditioning system on or off. An indicator light comes on when the air conditioning is turned on. This system cools and dehumidifies the air entering the vehicle. The air conditioning will not function if the fan is turned off. If air conditioning is selected with fan off, the indicator light flashes three times and then turns off. A slight change in engine performance may occur when the air conditioning compressor shuts off and turns on again. This is normal. The system is designed to make adjustments to help with fuel economy while still maintaining the selected temperature. The air conditioning system removes moisture from the air, so a small amount of water might drip under the vehicle while idling or after turning off the engine. This is normal.

(Recirculation): Press to turn the recirculation mode on or off. An indicator light comes on when the recirculation is on. This mode recirculates and helps to quickly cool the air inside the vehicle. It can be used to prevent outside air and odors from entering the vehicle. Recirculation is available in the bi-level and vent modes. This mode cannot be selected while in the floor, floor/defog or defrost modes. If you try to select the recirculation mode, the indicator flashes three times indicating it is not available in that mode. When the recirculation mode is turned on, the air conditioning turns on automatically. When it is hot enough outside, the recirculation mode may turn on automatically to help improve cooling performance. The indicator light will be lit to show this mode is active. If the recirculation button is pressed while in this mode, the light flashes three times and stays on to indicate that recirculation may not be shut off.

Rear Window Defogger

The rear window defogger uses a warming grid to remove fog or frost from the rear window when the key is in the ignition and turned to ON/RUN.

(Rear Defogger): Press to turn the rear window defogger on or off. After the button is first pressed the rear window defogger stays on for about 15 minutes. If turned on again, the defogger only runs for about seven and one-half minutes.

Notice: Do not use anything sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs would not be covered by the vehicle warranty. Do not attach a temporary vehicle license, tape, a decal or anything similar to the defogger grid.