GM Service Manual Online
For 1990-2009 cars only

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

Automatic Operation

AUTO (Automatic): When both the mode knob and the fan knob are in the AUTO mode and the temperature is set, the system will automatically control the inside temperature, the air delivery mode and the fan speed.


Object Number: 870782  Size: B1
  1. Press both the mode and the fan knobs to place the system in AUTO.
  2. Adjust the temperature to 75° F (24° C) on the display.
  3. Choosing the coldest or warmest temperature setting will not cause the system to heat or cool any faster. If you set the system at the warmest temperature setting, the system will remain in manual mode at that temperature and it will not go into automatic mode.

    In cold weather, the system will start at reduced fan speeds to avoid blowing cold air into your vehicle until warmer air is available. The system will start out blowing air at the floor but may change modes automatically as the vehicle warms up to maintain the chosen temperature setting. The length of time needed for warm up will depend on the outside temperature and the length of time that has elapsed since your vehicle was last driven.

  4. Wait for the system to regulate. This may take from 10 to 30 minutes. Then adjust the temperature, if necessary.

Do not cover the solar sensor located in the center of the instrument panel, near the windshield. For more information on the solar sensor, see "Sensors" later in this section.

To change the automatic climate control display from an English display to a metric display, push the OFF button located in the Driver Information Center (DIC) for several seconds. The display in the DIC will also change from an English to a metric display. To return to an English display, repeat the procedure.

Manual Operation

FAN: Turn the right knob clockwise or counterclockwise to increase or decrease the fan speed. Turning this knob cancels automatic operation and places the system in manual mode. Press the knob to return to automatic operation.

Temperature Control: Maintain the temperature inside the vehicle using the red and blue arrows located below the digital display. Push the red arrow for a warmer temperature level and the blue arrow for a cooler temperature level. Your selected temperature setting will be shown on the digital display for five seconds, and then the outside temperature will be displayed.

To change the current mode, use the left knob to select one of the following:

OFF: Turning the left knob to OFF will cause the fan to turn off and the airflow to be directed through the floor outlets. The display will show the outside temperature when the system is set to OFF.

(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 most of the remaining air to the floor outlets. Some air may be directed toward the windshield. In automatic operation, 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 with some air directed to the outboard outlets (for the side windows) and some air directed to the windshield.

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

(Recirculation): Press this button to limit the amount of outside air coming into 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 will come on. The recirculation mode cannot be used with the defrost mode.

A/C (Air Conditioning): Press this button to override the automatic system and 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. When in AUTO the air conditioning compressor will come on automatically, as necessary. On hot days, open the windows to let 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 the recirculation mode.
  3. Select A/C.
  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.

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.

Sensors

The solar sensor on your vehicle monitors the solar radiation and the air inside of your vehicle, then uses the information to maintain the selected temperature by initiating needed adjustments to the temperature, the fan speed and the air delivery system. The system may also supply cooler air to the side of the vehicle facing the sun. The recirculation mode will also be activated, as necessary. Do not cover the solar sensor located in the center of the instrument panel, near the windshield, or the system will not work properly.

Defogging and Defrosting

There are two modes 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.

(Defog): This mode directs the air equally between the windshield and the floor outlets. When you select this mode, the system turns off recirculation and runs the air conditioning compressor unless the outside temperature is at or below freezing.

(Defrost): This mode directs most of the air to the windshield and the outboard outlets (for the side windows), with some air directed to the floor outlets. In this mode, the system will automatically run the air conditioning compressor, unless the outside temperature is at or below freezing. 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. Be sure to clear as much snow from the rear window as possible. At speeds above 30 mph (48 km/h), the defogger will operate continuously until you press the REAR button again. After 10 minutes of driving below 30 mph (48 km/h), the defogger will turn off automatically. If you need additional warming time, push the button again. The system will then operate for five minutes before going off by itself. If your vehicle has heated outside rearview mirrors, the mirrors will heat to help clear fog or frost from the surface of the mirror when the rear window defogger button is pressed.

Notice: Do not use a razor blade or sharp object to clear the inside rear window. Do not adhere anything to the defogger grid lines in the rear glass. These actions may damage the rear defogger. Repairs would not be covered by your warranty.

Passenger Temperature Control

If your vehicle has this feature, the driver and the front-seat passenger can select separate temperature settings. This feature allows the passenger to select a temperature that is 8° F (4° C) warmer or cooler than the driver's selected temperature.


Object Number: 870788  Size: A3

The knob for this feature is located on the passenger's door. Turn the knob clockwise or counterclockwise to a warmer or cooler setting.