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: 811019  Size: B2

Automatic Operation

AUTO (Automatic): When this button is pressed and the temperature is set, the system will automatically control the inside temperature, the air delivery mode and the fan speed. AUTO will appear on the display.

  1. Press the AUTO button.
  2. Adjust the temperature to a comfortable setting between 70°F (21°C) and 80°F (27°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 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.

When your vehicle is first started, the display will show the driver's temperature setting, the fan speed and the air delivery mode.

When the ENG/MET (English/metric) button on the Driver Information Center (DIC) is pressed, the display will show readings in Fahrenheit or Celsius. Use the ENG/MET button to toggle between them.

Manual Operation

MODE : Pressing the MODE switch and changing the mode cancels automatic operation and places the system in manual mode. Press AUTO to return to automatic 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 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) a little air directed to the windshield. The MODE switch can also be used to select the floor/defog mode. Information on defogging and defrosting can be found later in this section.

(Fan): Press this switch to increase or decrease the fan speed. Pressing this switch cancels automatic operation and places the system in manual mode. Press AUTO to return to automatic operation. If the airflow seems low when the fan speed is at the highest setting, the passenger compartment air filter may need to be replaced. For more information, see Passenger Compartment Air Filter and Part A: Scheduled Maintenance Services .

(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 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 air-conditioning compressor also comes on.

TEMP (Driver's Temperature Knob): Press this knob to turn the climate control system on or off. Turn this knob clockwise or counterclockwise to manually increase or decrease the temperature inside your vehicle.

TEMP (Passenger's Temperature Knob): Press this knob to turn the passengers' climate control system controls on or off. Turn this knob to manually increase or decrease the temperature for the front passenger. If the passenger's climate controls are turned off, the driver's temperature knob will control the temperature for the entire vehicle.

A/C (Air Conditioning): Press this button to override the automatic system and turn the air-conditioning system on or off. 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 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 vent mode.
  2. Select the recirculation mode.
  3. Select A/C.
  4. Select the coolest temperature.
  5. Select the highest fan speed.
  6. Open all outlets.

Using these settings together for long periods of time may cause the air inside 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.

If your vehicle has the memory option, it can be used to recall your climate control settings. For more information, see Climate Controls Personalization .

Sensors


Object Number: 810884  Size: B3

The solar sensor on your vehicle monitors the solar radiation inside 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 middle of the instrument panel, near the windshield or the system will not work properly.

There is also an outside temperature sensor located under the front bumper and an inside temperature sensor located to the left of the ignition switch. These sensors read the outside and inside air temperature and help to maintain the selected temperature inside the vehicle. If you cover these sensors, it could cause a false reading in the temperature.

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

MODE : Press this switch until floor/defog appears on the display.

(Floor/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. The recirculation mode cannot be selected while in the floor/defog mode.

FRONT (Defrost): Pressing FRONT directs most of the air to the windshield and the side window outlets, with some air directed to the floor outlets. In this mode, the system will automatically turn off recirculation and run the air-conditioning compressor, unless the outside temperature is at or below freezing. Recirculation cannot be selected while in the 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.

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

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 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.

The heated outside rearview mirrors will heat to help clear fog or frost from the surface of the mirror when the REAR 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.