GM Service Manual Online
For 1990-2009 cars only

Climate Control System with Air Conditioning shown, Climate Control System without Air Conditioning similar


Object Number: 1511334  Size: B2

With this system you can control the heating and ventilation of your vehicle. You may also be able to control the cooling of your vehicle, if your vehicle has air conditioning. For a combination setting, move the control between two modes.

Temperature: Turn the left knob on the control panel to adjust the temperature of the air in the vehicle. Turn the knob clockwise or counterclockwise to increase or decrease the temperature.

(Air Conditioning): If your vehicle has air conditioning, press the left knob on the control panel to turn the air conditioning system on or off. An indicator light on the button will come on to let you know the air conditioning is activated. When the system is on, this setting cools and dehumidifies the air entering your vehicle. The air conditioning will not function if the fan is turned off. If air conditioning is selected with fan off, the indicator light will flash three times and then turn off. You may notice a slight change in engine performance when the air conditioning compressor turns off and turns on again. This is normal. The system is designed to make adjustments to help with fuel economy while still maintaining the selected temperature. Air conditioning does not operate at temperature below 40°F (4°C). In temperatures above 40°F (4°C) , the air conditioning cannot be turned off in defrost, floor/defog, and recirculation modes because it helps to remove moisture from the vehicle. It also helps to keep the windows clear. On hot days, open the windows to let the hot inside air escape; then close them. This helps 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 recirculation mode.
  3. Select the air conditioning to on.
  4. Select the coolest temperature.
  5. 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, turn the recirculation mode off.

(Fan): Turn the center knob on the control panel to control the fan speed. Turn the knob clockwise or counterclockwise to increase or decrease the fan speed.

(Off): Turn the center knob to this position to turn the fan off.

(Recirculation): Press the center knob on the control panel to recirculate air inside the vehicle and prevent outside air from coming in. It can be used to prevent outside odors from entering your vehicle and cool the air inside your vehicle more quickly. Press this button to turn the recirculation mode on or off. An indicator light on the button will come on to let you know the recirculation mode is activated. Recirculation is available in the bi-level and vent modes. If recirculation is selected in either floor/heat, floor/defog, or defrost mode, the LED light will flash three times indicating recirculation is not available in that mode. The right knob on the control panel is used to direct the airflow inside your vehicle. Turn the knob to select one of the following modes:

(Vent): Turn the right knob on the control panel to this mode to direct air to the instrument panel outlets.

(Bi-Level): Turn the right knob on the control panel to this mode to direct air to the instrument panel outlets, and the remaining air to the floor outlets and the defroster and side window outlets. Cooler air is directed to the upper outlets and warmer air to the floor outlets.

(Floor): Turn the right knob on the control panel to this mode to direct most of the air to the floor outlets. The remaining air is directed to the side window and defroster outlets. If there is little or no airflow on the passenger side, make sure that the carpet covering is tucked under the floor outlets.

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. Use a temperature setting that provides warm air. The warmer the air the quicker the windows will clear.

To prevent fogging on the inside of the windows in modes other than floor/defog and defrost, make sure the air conditioning compressor, if the vehicle has one, is on and recirculation mode is off.

(Floor/Defog): Turn the right knob on the control panel to this mode to direct the air to the windshield, the side window outlets, and to the floor outlets. When you select this mode, the system runs the air conditioning compressor unless the outside temperature is near freezing or below.

(Defrost): Turn the right knob on the control panel to this mode to direct most of the air to the windshield, and the side window outlets. When you select this mode, the system runs the air conditioning compressor unless the outside temperature is near or below freezing.

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. Be sure to clear as much snow from the rear window as possible. An indicator light on the knob will come on to show that the rear window defogger is activated. The rear window defogger will turn off about fifteen minutes after the knob is pressed. If turned on again, the defogger will run for about seven and one-half minutes before turning off. If the vehicle speed is greater than 50 mph (80 km/h) and the rear defogger is active, it will remain on as long as the speed is greater than 50 mph (80 km/h) . The defogger can also be turned off by pressing the knob again or by turning off the engine.

(Rear Defogger): Press the right knob on the control panel to turn the rear window defogger on or off.

Do not operate rear defogger when convertible top is down.

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.