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: 807316  Size: B2

When your vehicle is first started, the display will show the driver's temperature setting, the fan speed and the air delivery for approximately five seconds; then it will show the outside temperature.

The digital display will show readings in Fahrenheit or Celsius by pressing the E/M (English/metric) button on the Driver Information Center (DIC).

Automatic Operation

AUTO (Automatic): Press the AUTO button to place the entire system in the automatic mode. When automatic operation is active, the system will automatically control the inside temperature, the air delivery mode and the fan speed.

After a five-second display of the current settings, only the word AUTO and the outside temperature will be shown on the digital display unless the system is set to full cold 60°F (16°C) or full hot 90°F (32°C), then the word AUTO will not display. The system will operate to achieve your comfort set temperature as quickly as possible. The AUTO control system works best with the windows up and the removable roof installed or the convertible top up.

  1. Press the AUTO button.
  2. Adjust the temperature to a comfortable setting between 60°F (16°C) or full hot 90°F (32°C).
  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 coldest or 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 at 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 "Solar Sensor" later in this section.

Manual Operation

OFF: Press this button to turn off the climate control system. This is the only setting that fully shuts off the fan. The digital display will show only the outside temperature. You can still adjust the driver's set temperature, the passenger temperature offset and the air intake mode while in OFF.

MODE: Press this button to manually lock in the current air delivery setting and to stop the automatic mode control. Pressing the MODE button will delete AUTO from the digital display and the mode graphics will be shown. To change the setting, press the MODE button again. The AUTO button must be pressed to return to the automatic mode selection. To change the current mode, select one of the following:

(Vent): This mode directs most of the air to the instrument panel outlets, with a very small amount of air directed to the floor 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. 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 MODE button can also be used to select the defog mode. Information on defogging and defrosting can be found later in this section.

(Fan): Press the button with the fan symbol to manually increase or decrease the fan speed. Keep pressing the up or down arrow on this switch until the desired fan speed appears on the display. Pressing the arrows will delete AUTO from the digital display. The fan graphics with the fan speed bars will be shown. To increase the fan speed so that more air flows into the vehicle, press the up arrow on the fan switch. To decrease the fan speed and airflow, press the down arrow. The AUTO button must be pressed to return to the automatic fan control.

(Outside Air): Press this button to turn the outside air mode on or off. When this mode is on, outside air will circulate throughout 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, but cannot be used with the recirculation mode. When in the AUTO mode, the system automatically selects outside air instead of recirculation, as required, to control the temperature in the vehicle. By pressing outside air, the system will lock into the outside air mode. Any adjustment to the air intake must then be made manually. Outside air should be used when trying to defrost or defog windows to help reduce moisture inside of the vehicle. If you are in city traffic, 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 stale, be sure to return to the outside air mode periodically.

(Recirculation): 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 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 air-conditioning compressor also comes on. The recirculation mode cannot be used with the outside air mode. When in the AUTO mode, the system automatically selects recirculation to cool the vehicle's temperature. By pressing this button, the system will lock into recirculation mode. Any adjustment to the air intake must then be made manually. Recirculation is not available when using the defrost or defog mode because outside air is needed to reduce moisture inside of the vehicle. Operating the system in the recirculation mode may cause fogging of the vehicle's windows when the weather is cold and damp. To clear the fog, switch the system to either the defog or defrost mode and increase the fan speed. To avoid re-fogging of the windows, operate the system in the outside air mode.

Temperature Control: The DRIVER knob changes the temperature on the driver's and passenger's side of the vehicle. Turn the knob clockwise or counterclockwise to manually increase or decrease the temperature inside your vehicle. Whenever you turn this knob, the temperature will be displayed for approximately five seconds along with the current fan speed and air delivery mode. The PASSENGER knob changes the temperature on the passenger's side of the vehicle. When the knob is in the 12 o'clock position, the passenger's temperature is the same as the driver's. Turn the knob clockwise for warmer air on the passenger's side or counterclockwise for cooler air. If the driver-set temperature is set at full cold 60°F (16°C) or full hot 90°F (32°C), turning the PASSENGER knob has no effect because the system is locked at a maximum setting.

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 the air conditioning is activated. When in AUTO, the air-conditioning compressor will come on automatically, as necessary. Air conditioning does not operate at temperatures below approximately 35°F to 40°F (2°C to 4°C). The air conditioning cannot be turned off in defrost and defog, as it helps to remove moisture from the vehicle. It also helps to keep the windows clear.

You may notice a slight change in engine performance when the air-conditioning compressor shuts 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.

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, do the following:

  1. Select the vent mode.
  2. Select recirculate mode.
  3. Select the 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 uses the information to maintain the selected temperature when operating in AUTO mode 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 on the top right side of the instrument panel near the windshield or the system will not work properly.

There is also a sensor located behind the front bumper. 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 give a false reading in the temperature.

If the outside temperature goes up, the displayed temperature will not change until:

    • The vehicle's speed is above 16 mph (26 km/h) for one and a half minutes.
    • The vehicle's speed is above 45 mph (72 km/h) for one minute.

These delays prevent false readings. If the temperature goes down, the outside temperature will be shown when you start the vehicle. If it has been turned off for less than three hours, the temperature will be recalled from the previous vehicle operation.

There is also an inside temperature sensor located to the left of the ignition switch. The automatic climate control system uses this sensor to receive information, so if you block or cover it, the system will not function properly.

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

Press the MODE button until the defog mode appears on the display.

(Defog): This mode directs the air equally between the windshield and the floor outlets with a small amount to the side window 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. An indicator light in the A/C button will come on to let you know that the air-conditioning compressor is activated. The recirculation mode cannot be selected while in the defog mode.

FRONT: Pressing this button directs most of the air to the windshield, with a small amount directed to the side window outlets. The light on the button will come on and the digital display will show the defrost mode symbol and fan speed when the front defrost mode is being used. In this mode, the system will automatically turn off the recirculation and run the air-conditioning compressor, unless the outside temperature is at or below freezing. An indicator light in the A/C button will come on to let you know that the air-conditioning compressor is activated. Recirculation cannot be selected while in the defrost mode. Pressing this button again will return the system to the last operating mode and the air intake mode will be in outside air.

If the system is in FRONT defrost when you shut the engine off, it will restart in FRONT defrost unless the engine is off for longer than 40 minutes. If the engine is off longer than 40 minutes, the system will restart in the operating mode that was set prior to FRONT defrost and the air intake mode will be in outside air. Do not drive until all windows are clear.

Rear Window Defogger

The rear window defogger uses a warming grid to remove fog or frost from the rear window.

The rear window defogger will only work when the engine is running.

REAR: Press this button to turn the rear window defogger on. Be sure to clear as much snow from the rear window as possible. An indicator light in the button will come on to let you know that the rear window defogger is activated.

The rear window defogger will automatically turn off approximately 15 minutes after the button is pressed. If turned on again, the defogger will only run for approximately seven minutes before turning off. The defogger can also be turned off by pressing the button again or by turning off the engine.

Your vehicle has heated outside rearview mirrors. The mirrors will heat to help clear fog or frost from the surface of the mirrors when the rear window defog button is pressed.

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.