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: 807163  Size: B2

Automatic Operation

AUTO (Automatic): Press the AUTO button for automatic control of the inside temperature, the air delivery mode and the fan speed.

  1. Press the AUTO button. Whenever this button is pressed, the display will show the current settings for five seconds before returning the display to the exterior temperature.
  2. Adjust the temperature to 75° F (24° C).
  3. Choosing the coldest or warmest temperature setting will not cause the system to cool or heat any faster. If you set the system at the coldest or warmest temperature setting, the system will remain at the maximum cold or hot setting and fan speed.

    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.

Manual Operation

DRIVER (Driver's Side Temperature): The knob on the left is used to change the temperature of the air coming through the system on the driver's side of the vehicle. Push this knob to turn the system on and off. Turn the knob toward the blue area to decrease the set temperature, and toward the red area to increase the set temperature. When this knob is adjusted, the word DRIVER will be displayed under the set temperature. When the passenger's set temperature is not active, this knob controls both the driver's and passenger's side, and both DRIVER and PASS will be displayed under the set temperature.

PASS (Passenger's Side Temperature): The knob on the right is used to change the temperature of the air coming through the system on the passenger's side of the vehicle. Push this knob to turn the system on and off. Turn the knob toward the blue area to decrease the set temperature, and toward the red area to increase the set temperature. When this knob is adjusted, only the word PASS will be displayed under the set temperature.

(Fan): Press the Fan button to display and hold the current fan speed while in manual mode. Press the HIGH side to increase fan speed and the LOW side to decrease the fan speed.

MODE: Press this button repeatedly to cycle through and choose the mode of air delivery into the vehicle. The system will stay in the selected mode until MODE is pressed again or until the AUTO button is pressed.

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

BI-LEVEL: This mode directs airflow through the instrument panel outlets and slightly warmer air through the floor outlets.

PANEL: This mode directs airflow through the instrument panel outlets. Whenever MODE is pressed, the display will show the current system settings for five seconds before returning the display to the exterior temperature. The mode button can also be used to select the DEFOG mode. Information on defogging and defrosting can be found later in this section.

OUTSIDE AIR: Press this button to turn the OUTSIDE AIR mode on or off. When this mode is on, outside air will circulate through your vehicle. When the button is pressed, an indicator light in the button will come on to let you know that it is activated. The OUTSIDE AIR mode can be used with all modes except the recirculation mode. If you are in city traffic, and your vehicle is stopped and idling, or the weather is hot, the system may switch from the OUTSIDE AIR mode to the recirculation mode. To prevent the air inside of your vehicle from becoming too stale, be sure to return to the outside air mode periodically.

RECIRC (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 FRONT 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 it is activated. When in AUTO, the air conditioning compressor will come on automatically, as necessary. The air conditioning compressor will also run when you select the FRONT defrost mode and outside temperatures are above freezing. 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, press the AUTO button and the system will automatically enter recirculation mode and the temperature will be at the full cold position for maximum cooling. 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.

There is also an EXT (exterior) temperature sensor located behind the front grill. This sensor reads the outside air temperature and helps to maintain the temperature inside the vehicle. Any cover on the front of the vehicle could cause a false reading in the temperature.

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 your windshield. Use the defog mode to clear the windows of fog or moisture and warm the passengers. Use the FRONT defrost mode to remove fog or frost from the windshield more quickly.

Press the MODE button until DEFOG appears to select this function. Press the FRONT button to select the defrost function.

DEFOG: This mode directs the air equally between the windshield and the floor outlets.

FRONT (Defrost): Pressing this button directs most of the air to the windshield and the outboard outlets for the side windows, with some air directed to 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. The recirculation mode cannot be selected while in the FRONT 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. Be sure to clear as much snow from the rear window as possible.

The rear window defogger will turn off about 10 minutes after the button is pressed. If turned on again, the defogger will only run for about five minutes before turning off. If you maintain a speed above 30 mph (48 km/h), the rear defogger will not turn off automatically to help keep the rear glass clear. The defogger can also be turned off by pressing the button again or by turning off the engine.

If your vehicle has outside heated 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.