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: 838771  Size: B2

Operation

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

MAX: This mode is used for maximum cooling. It will recirculate much of the air inside your vehicle. It maximizes your air conditioner's performance and your vehicle's fuel economy. The air-conditioning compressor will run automatically in this mode when it is needed to help dry the air in the vehicle.

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

(Bi-Level): This mode directs half of the air to the instrument panel outlets, then directs most of the remaining air to the floor outlets with some air directed at the side windows.

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

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.

Temperature Control: Turn the center knob clockwise or counterclockwise to manually 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 above the button will come on to let you know that air conditioning is activated. The fan knob must be set to a speed for the air conditioning to operate.

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:

  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 clockwise or counterclockwise to select defog or defrost mode.

(Defog): This mode directs half of the air to the windshield with most of the remaining air directed to the floor outlets and some air directed at 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.

FRONT (Defrost): This mode directs most of the air to the windshield, with some air directed to the floor outlets. In this mode, the system will automatically turn off recirculation and run the air-conditioning compressor, unless the outside temperature is at or below freezing. Recirculation cannot be selected while in the defrost mode. Do not drive the vehicle until all the windows are clear.

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 above the button will come on to let you 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.