GM Service Manual Online
For 1990-2009 cars only

With this system you can control the heating, cooling and ventilation for your vehicle.


Object Number: 838768  Size: B2

Operation

To change the current mode, turn the right knob to select one of the following:

(Vent): This mode directs air to the instrument panel outlets.

(Bi-Level): This mode directs half of the air to the instrument panel outlets, and then directs most of the remaining air to the floor outlets. Some air may be directed toward the side windows.

(Floor): This mode directs most of the air to the floor outlets with some air directed to the side window outlets.

The right knob can also be used to select defog or defrost modes. Information on defogging and defrosting can be found later in this section.

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

(Outside Air): Press this button to turn the outside air mode on or off. When this mode is on, outside air will circulate throughout your vehicle. When the button is pressed, an indicator light in the button will come on to let you know that it is activated. The outside air mode can be used with all modes, but it cannot be used with the recirculation mode. Pressing this button will cancel the recirculation mode.

(Recirculation): This mode keeps outside air from coming in the vehicle. It can be used to prevent outside air and odors from entering your vehicle or to help heat or cool the air inside your vehicle more quickly. Press this button to turn the recirculation mode on or off. When the button is pressed, an indicator light in the button will come on to let you know that it is activated. The air-conditioning compressor comes on. The recirculation mode can be used with vent, bi-level, or floor modes, but it cannot be used with the defog or defrost modes. Pressing this button will cancel the outside air mode. When you switch to the defog or defrost modes the system will automatically move from recirculation to outside air. When you move the mode knob back to another mode, the system will move back into recirculation. When the car is turned off and back on the system will default to outside air automatically.

Temperature Control: Turn the center knob clockwise or counterclockwise to increase or decrease the temperature inside your vehicle.

When it's cold outside 0°F (-18°C) or lower, use the engine coolant heater, if equipped, to provide warmer air faster to your vehicle. An engine coolant heater warms the coolant that the engine uses to provide heat to warm the inside of your vehicle. For more information, see Engine Coolant Heater .

A/C (Air Conditioning): Press this button to turn the air-conditioning system on or off. When A/C is pressed, an indicator light in the button will come on to let you know that air conditioning is activated.

On hot days, open the windows to let hot inside air escape; then close them. This helps to reduce the time it takes for your 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 A/C.
  4. Select the recirculation mode.
  5. Select the coolest temperature.

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

The air-conditioning system removes moisture from the air, so you may sometimes notice a small amount of water dripping underneath your vehicle while idling or after turning off the engine. This is normal.

Defogging and Defrosting

Fog on the inside of windows is a result of high humidity (moisture) condensing on the cool window glass. This can be minimized if the climate control system is used properly. There are two modes to choose from to clear fog or frost from your windshield. Use the defog mode to clear the windows of fog or moisture and warm the passengers. Use the defrost mode to remove fog or frost from the windshield more quickly.

Turn the right knob to select the defog or defrost mode.

(Defog): This mode directs half of the air to the windshield and half to the floor outlets with a small amount directed to the side windows. When you select this mode, the system turns off recirculation automatically and runs the air-conditioning compressor unless the outside temperature is at or below freezing. 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 directs most of the air to the windshield with some air directed to the floor vents. In this mode, the system will automatically force outside air into your vehicle and run the air-conditioning compressor. Recirculation cannot be selected while in the defrost mode.

Rear Window Defogger

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

REAR: Press this button to turn the rear window defogger on or off. An indicator light in the button will come on to let your know that the rear window defogger is activated. Be sure to clear as much snow from the rear window as possible.

The rear window defogger will turn off approximately 10 minutes after the button is pressed. If turned on again, the defogger will only run for approximately five minutes before turning off. The defogger can also be turned off by pressing the button again or 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.