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: 855338  Size: B1

Operation

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

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

(Bi-Level): This mode directs approximately half of the air to the instrument panel outlets, and then directs the remaining air to the floor outlets. Cooler air is directed to the upper outlets and warmer air to the floor outlets.

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

The right knob can also be used to select defrost mode. 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. In any setting other than off, the fan will run continuously with the ignition on. The fan must be turned on to run the air conditioning compressor.

(Off): To turn the fan off, turn the knob all the way counterclockwise to the off position.

(Recirculate): 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. An indicator light will come on in this mode. The air-conditioning compressor also comes on. Operation in this mode during periods of high humidity and cool outside temperatures may result in increased window fogging. If window fogging is experienced, select the defrost mode.

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

(Air Conditioning): Press this button to turn the air-conditioning system on or off. When this button is pressed, an indicator light above the button will come on to let you know 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 your vehicle to cool down. It also helps the system to operate more efficiently.

For quick cool down on hot days:

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

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, switch from recirculation to vent, bi-level or floor.

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 clear fog or frost from your windshield and side windows. 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. For best results, clear all snow and ice from the windshield before defrosting.

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

(Defog): This mode directs half of the air to the windshield and the side window outlets and half to the floor outlets. When you select this mode, the system runs the air-conditioning compressor unless the outside temperature is at or below freezing. The air-conditioning indicator light will also be on in this setting. 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, with some air directed to the side window outlets and the floor outlets. When you select this mode, the system runs the air-conditioning compressor unless the outside temperature is at or below freezing. The air-conditioning indicator light will also be on in this setting.

To defog the side windows, set the right knob to floor and the fan knob to the highest setting. You can use the air conditioning while in this setting by pressing the air conditioning button. In both cases, aim the side outlets toward the side windows. For increased airflow to the side outlets, close the center outlets. 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 from the rear window.

The rear window defogger will only work when the ignition is in RUN.

(Rear): Press the button to turn the rear window defogger on or off. Be sure to clear as much snow from the rear window as possible. An indicator light above the button will come on to let you know that the rear window defogger is activated.

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.