GM Service Manual Online
For 1990-2009 cars only

The heating, cooling, and ventilation for the vehicle can be controlled with this system. For vehicles with the remote start feature, the climate control system functions as part of the remote start feature. See Remote Keyless Entry (RKE) System Operation.


Object Number: 2047643  Size: B2
  1. Fan Control

  2. Recirculation

  3. Temperature Control

  4. Outside Air

  5. Air Delivery Mode Control

  6. Air Conditioning

  7. Rear Window Defogger

(Fan Control): Turn the knob clockwise or counterclockwise to increase or decrease the fan speed. The fan must be on to run the air conditioning compressor.

Temperature Control: Turn the knob clockwise or counterclockwise to increase or decrease the temperature inside the vehicle. When it is cold outside 0°F (-18°C) or lower, use the engine coolant heater, if the vehicle has one, to quickly provide warmer air. An engine coolant heater warms coolant that the engine uses to warm the inside of the vehicle. For more information, see Engine Coolant Heater.

Air Delivery Mode Control: Turn the knob clockwise or counterclockwise to change the air delivery settings.

Select from the following modes:

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

(Bi-Level): Air is divided between the air to the instrument panel and floor outlets. Some air may be directed toward the side windows.

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

(Defog): This mode clears the windows of fog or moisture. Air is directed to the windshield and floor outlets, with some air directed to the side windows. When this mode is selected, the system automatically turns off recirculation and tuns the air conditioning compressor unless the outside temperature is at or below freezing. The air conditioning compressor operates although the indicator light is not on. The air conditioning indicator light turns off when defog is selected. If the air conditioning button is pressed while in defog mode, the indicator light turns on. If the button is pressed again, the light turns off. The recirculation mode cannot be selected while in the defog mode. Do not drive the vehicle until all the windows are clear.

(Defrost): This mode clears the windshield of fog or frost more quickly. Air is directed to the windshield, with some air directed to the floor vents. In this mode, the system automatically forces outside air into the vehicle. The air conditioning compressor runs unless the outside temperature is at or below freezing. The air conditioning compressor operates although the indicator light is not on. The air conditioning indicator light turns off when defrost is selected. If the air conditioning button is pressed while in defrost mode, the indicator light turns on. If the button is pressed again, the light turns off. Recirculation cannot be selected while in the defrost mode.

To help clear the windshield quickly, do the following:

  1. Select the defrost mode.
  2. Select the highest temperature.
  3. Select the highest fan speed.
(Outside Air): Press the right side of the button to turn the outside air mode on. An indicator light comes on to show that it is on. Air from outside the vehicle circulates throughout the vehicle. The outside air mode can be used with all modes, except the recirculation mode. Press again to cancel the recirculation mode.

(Recirculation): Press the left side of the button to turn the recirculation mode on. An indicator light comes on to show that it is on. The air inside the vehicle is recirculated through the climate control system and throughout the vehicle, not from outside. This helps to limit the odors entering the vehicle and maximize air conditioning performance. The indicator light flashes three times if you try to use recirculation in a mode that it can not be used in. Use this mode only when it is needed for comfort, since window fogging occurs if the air conditioning compressor is not engaged. Press to cancel the outside air mode. When you switch to the defog or defrost modes the system automatically moves from recirculation to outside air. When the vehicle or fan is turned off and back on, the system automatically defaults to outside air.

(Air Conditioning): Press to turn the air conditioning system on or off. An indicator light comes on to indicate that the air conditioning is on.

The air conditioning system removes moisture from the air, so sometimes a small amount of water drips under the vehicle while it is idling or after the engine is turned off. This is normal.

Maximum Air Conditioning

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, do the following:

  1. Select the vent mode.
  2. Select the highest fan speed.
  3. Select air conditioning.
  4. Select the recirculation mode.
  5. Select the coolest temperature.

Using these settings together for long periods of time can 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 the recirculation mode off.

Rear Window Defogger

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

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

If driving below 50 mph (80 km/h), 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 and one-half minutes before turning off. The defogger can also be turned off by turning off the engine.

If the vehicle's speed is maintained above 50 mph (80 km/h), the rear window defogger remains on once the button is pressed.

If the vehicle has the remote start feature, the rear defogger automatically turns on if it is cold outside. When the vehicle transitions out of the remote start mode, the rear defogger turns off. See Remote Keyless Entry (RKE) System Operation.

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.

Remote Vehicle Start

If the vehicle has the remote start feature, it will turn on using the last settings selected on the climate control before the vehicle was turned off.

The fan and air delivery knobs can be used during remote start. The buttons will not work until the ignition is turned on by the key.

The climate control system changes back to manual operation when the vehicle key is turned to ON/RUN.