GM Service Manual Online
For 1990-2009 cars only

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


Object Number: 2049005  Size: B2
  1. Fan Control

  2. Driver and Passenger Temperature Controls

  3. Air Delivery Mode Control

  4. Recirculation

  5. Air Conditioning

  6. Rear Window Defogger

Driver's Side Temperature Lever: Raise or lower the lever to increase or decrease the temperature on the driver's side of the vehicle.

Passenger Side Temperature Lever: Raise or lower the lever to increase or decrease the temperature on the passenger side of the vehicle. This right lever also adjusts the temperature to the rear seat outlets.

When the temperature outside is 0°F (-18°C) or lower, use the engine coolant heater, if the vehicle has one, to provide warmer air faster to the vehicle.

(Fan Control): Turn clockwise or counterclockwise to increase or decrease the fan speed. If the knob is in off mode, outside air still enters the vehicle, and is directed based on the position of the air delivery mode knob. The temperature can still be adjusted using the temperature knob.

Air Delivery Mode Control: Turn clockwise or counterclockwise to change the airflow direction inside the vehicle.

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

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

(Bi-Level): Air is divided between the instrument panel and floor outlets. Some air is directed toward the windshield and the side window outlets. Cooler air is directed to the upper vents and warmer air to the floor outlets.

(Floor): Air is directed to the floor outlets, with some air directed to the windshield and the side window outlets. The recirculation button cannot be selected while in floor mode.

(Defog): This mode clears the windows of fog or moisture. Air is directed to the floor, windshield and side window outlets. The recirculation button cannot be selected while in defog mode.

(Defrost) : This mode clears the windows of fog or frost more quickly. Air is directed to the windshield and the side window outlets, with some air directed to the floor outlets. The air conditioning compressor may run to dehumidify the air to prevent window fogging. The recirculation button cannot be selected while in defrost 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 and the system begins to cool and dehumidify the air inside of the vehicle. You may notice a slight change in engine performance when the air conditioning compressor shuts off and turns on again. This is normal.

(Recirculation): Press to turn the recirculation mode on. An indicator light comes to show that the 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 will also come on when this mode is activated. While in recirculation mode, the windows may fog when the weather is cold and damp. To clear the fog, select either the defog or defrost mode and increase fan speed.

Rear Window Defogger

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

(Rear): Press to turn the rear window defogger on or off. An indicator light in the button comes on to show that the rear window defogger is on. The rear window defogger automatically turns off approximately ten minutes after the button is pressed.

For vehicles with heated mirrors, they turn on when the rear window defogger button is pressed.

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.