GM Service Manual Online
For 1990-2009 cars only

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

Uplevel shown, Base similar


Object Number: 1272971  Size: B2
(Fan): Turn the left knob clockwise or counterclockwise to increase or decrease the fan speed. In any setting other than off, the fan runs continuously with the ignition in ON/RUN. The fan must be on for the air conditioning compressor to run.

To change the current mode, select one of the following from the middle knob:

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

(Bi-Level): This mode splits the air between the instrument panel outlets and the floor outlets.

(Floor): This mode directs most of the air to the floor outlets. Some of the air will also be directed to the windshield, instrument panel side outlets, and the rear outlets. Be sure to keep the area under the front seats clear to allow the flow of air to the rear compartment.

Temperature Control: Turn the right knob clockwise or counterclockwise to manually increase or decrease the temperature inside the vehicle. Turn the knob to the blue area to get cool air and to the red area to get warm air.

A/C (Air Conditioning): If your vehicle has air conditioning, follow these steps to use the system. Start the engine and set the fan control knob to the desired fan speed. The air conditioning compressor does not operate when the fan control knob is turned to OFF. Press the A/C button to turn the air conditioning system on and off. When A/C is pressed, an indicator light in the button comes on to show that the 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 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. Press the A/C button.
  4. Press the recirculation button.
  5. Select the coolest temperature.

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 the recirculation mode off.

The air conditioning system removes moisture from the air, so a small amount of water might drip underneath the vehicle while idling or after turning off the engine. This is normal.

(Recirculation): This mode keeps outside air from coming into the vehicle. It can be used to prevent outside air and odors from entering the vehicle or to help heat or cool the air inside the vehicle more quickly. Press this button to turn the recirculation mode on. When the button is pressed, an indicator light in the button comes on. Press this button again to return to outside air mode. Using the recirculation mode for extended periods may cause your windows to fog. If this happens, select the defrost mode.

Defogging and Defrosting

Fog on the inside of windows is a result of high humidity or moisture condensing on the cool window glass. This can be minimized if the climate control system is used properly. There are two modes to clear fog or frost from the 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.

(Defog): This mode directs most of the air to the windshield and the floor outlets. A small amount of air is also directed to the outboard outlets for the side windows and to the instrument panel side outlets. When this mode is selected, the system runs the air-conditioning compressor. To defog the windows faster, turn the temperature control knob clockwise to the warmest setting.

(Defrost): This mode directs most of the air to the windshield and the outboard outlets for the side windows. A small amount of air is also directed to the instrument panel side outlets. When this mode is selected, the system runs the air-conditioning compressor. To defrost the windows faster, turn the temperature control knob clockwise to the warmest setting.

Front Heated Windshield

Your vehicle may have a heated front windshield which can be used with defog and defrost. This feature will only work when the ignition is turned to ON/RUN.

The front heated windshield uses a heated element to remove fog or frost from the bottom of the windshield.

(Rear): Press this button located below the audio system. An indicator light in the button comes on to show that the feature is activated. The front windshield heater will turn off about ten minutes after the button is pressed. To manually turn off the heater, press the button again or turn off the engine. See "Rear Window and Outside Mirror Defogger" later in this section for more information on this button.

Rear Window and Outside Mirror Defogger

Your vehicle may have a rear window and outside mirror defogger. This feature will only work when the ignition is turned to ON/RUN.

The rear window defogger uses a warming grid to remove fog or frost from the rear window. Before using this feature, clear as much snow from the rear window as possible.

(Rear): Press this button. An indicator light in the button comes on to show that the rear window defogger is activated.

The rear window defogger will turn off about 10 minutes after the button is pressed. To manually turn off the defogger, press the button again or turn off the engine. See "Front Heated Windshield" earlier in this section for more information on this button.

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.