GM Service Manual Online
For 1990-2009 cars only

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

Vehicles with Air Conditioning shown, without Air Conditioning similar


Object Number: 2051400  Size: B2
  1. Air Delivery Mode Control

  2. Fan Control

  3. Temperature Control

  4. Air Conditioning

  5. Rear Window Defogger

  6. Recirculation

To change the current mode, select one of the following:

(Off): Turn the fan control to this position to turn the fan off.

Temperature Control: Turn clockwise or counterclockwise to increase or decrease the temperature.

(Fan Control): Turn clockwise or counterclockwise to increase or decrease the fan speed. In any setting other than off, the fan will run continuously with the ignition on. The fan must be turned on to run the air conditioning compressor.

Air Delivery Mode Control: Turn clockwise or counterclockwise to change the direction of the airflow inside the vehicle. Select from the following modes:

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

(Bi-Level): Air is divided between the instrument panel outlets and the floor outlets. Cooler air is directed to the upper outlets and warmer air to the floor outlets.

(Floor): Air is directed to the floor outlets, with some air directed to the windshield and side windows.

(Defog): This mode clears the windows of fog or moisture. Air is directed to the windshield, side window, and floor outlets. To defog the windows faster, turn the temperature control knob clockwise to the warmest setting. In this mode, the system runs the air conditioning compressor.

(Defrost): This mode removes fog or frost from the windshield more quickly. Air is directed to the windshield, with some air directed to the side window outlets and the floor outlets. To defrost the windows faster, turn the temperature control knob clockwise to the warmest setting. In this mode, the system runs the air conditioning compressor. For best results, clear all snow and ice from the windshield before defrosting.

(Air Conditioning): For vehicles with air conditioning, press this button to turn the air conditioning system on or off. An indicator light comes on to show that the air conditioning is on.

On hot days, open the windows to let hot inside air escape; then close them. This helps to reduce the time it takes for the vehicle to cool down. It also helps the system to operate more efficiently.

For quick cool down on hot days:

  1. Select the mode.
  2. Select the mode.
  3. Select .
  4. Select the coolest temperature.
  5. Select the highest fan speed.

Using these settings together for long periods of time may cause the air inside of the vehicle to become too dry. To prevent this from happening, after the air in the vehicle has cooled, turn off the recirculation by pressing the button again.

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.

The air conditioning compressor cannot be turned on when the fan is off.

(Recirculation): Press to turn the recirculation mode on. An indicator light comes on to show that recirculation is on. This mode recirculates and helps to quickly cool the air inside the vehicle. It can be used to help prevent outside air and odors from entering the vehicle. The air conditioning compressor also comes on. Recirculation is not available for floor, defog and defrost modes. If recirculation is selected in any of these modes, the recirculate indicator light flashes five times and outside air will be delivered. Operation in this mode during periods of high humidity and cool outside temperatures may result in increased window fogging. If window fogging is experienced, select the defrost mode.

Outside Air: This mode allows outside air to circulate through the vehicle. This mode is automatically active if recirculate is not selected. There is no button for outside air.

Rear Window Defogger

The rear window defogger uses a warming grid to remove fog from the rear window.

The rear window defogger only works when the ignition is in ON/RUN.

(Rear): Press to turn the rear window defogger on or off. Be sure to clear as much snow from the rear window as possible. An indicator light comes on to show that the rear window defogger is on.

The rear window defogger turns off about 15 minutes after the button is pressed. If turned on again, the defogger only runs for about seven minutes before turning off. If the vehicle is moving faster than 50 mph (80 kph), the rear defogger will stay on. The defogger can also be turned off by turning off the engine.

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.