GM Service Manual Online
For 1990-2009 cars only

If the vehicle has this system, the heating, cooling, and ventilation can be automatically controlled in the vehicle.


Object Number: 2047635  Size: B2
  1. Fan Control

  2. Air Conditioning

  3. Recirculation

  4. Outside Air

  5. Rear Window Defogger

  6. Air Delivery Mode Control

  7. Display

  8. Temperature Control

Automatic Operation

AUTO (Automatic): Select AUTO on both the fan speed control and the air delivery mode control knobs to activate the automatic system. Automatic operation controls the inside temperature and air delivery.

Use the steps below to place the climate control system in automatic mode:

  1. Turn the fan knob and the air delivery mode knob to AUTO.
  2. The display shows the current set temperature. When auto is selected, the air conditioning operation and air inlet is automatically controlled. The air conditioning compressor runs when the outside temperature is over about 40°F (4°C). The air inlet is normally set to outside air. If it is hot outside, the air inlet can automatically switch to recirculate inside air to help quickly cool down the vehicle.

  3. Set the temperature.
  4. To find your comfort setting, start with an initial temperature setting and allow about 20 minutes for the system to regulate. Press and to adjust the temperature setting as necessary. If the temperature setting of 60°F (15°C) is chosen the system remains at the maximum cooling setting. If the temperature setting of 90°F (32°C) is chosen the system remains at the maximum heat setting. Choosing either maximum setting will not cause the vehicle to heat or cool faster.

    Be careful not to cover the sensor located on the top of the instrument panel near the windshield. This sensor regulates air temperature based on sun load, and also turns on the headlamps.

    Also be careful not to cover the sensor grille on the lower right side of the climate control faceplate. This senses the inside vehicle temperature needed for proper regulation.

    To avoid blowing cold air at start-up in cold weather, the system delays turning on the fan until warm air is available. The length of delay depends on the engine coolant temperature. Turning the fan knob overrides this delay and change the fan to a selected speed.

If the vehicle has the remote start feature, the climate control display initially shows "RS" in place of the temperature to indicate the remote start has been activated. The remote start system turns on using the last temperature selected before the vehicle was last turned off.

For best performance, turn the fan and mode knobs to the AUTO position. The fan speed and air delivery modes will change to achieve the best comfort.

If the outside air temperature is below 45°F and the air delivery mode knob is set to AUTO, the automatic climate control system starts in the defrost mode to clear the window.

The automatic climate control changes back to manual operation by turning the vehicle on with the key.

Manual Operation

The air delivery mode or fan speed can be manually adjusted.

(Off): Turns off the entire climate control system. Outside air still enters the vehicle, and is directed to the floor. This direction can be changed by adjusting the air delivery mode position.

(Fan Control): Turn the knob clockwise or counterclockwise to increase or decrease the fan speed.

Temperature Control: Press the up and down arrows to increase or decrease the temperature inside the vehicle.

Air Delivery Mode Control: Turn the knob clockwise or counterclockwise to change the air delivery settings.

Select from the following modes:

(Vent): Air is directed to the instrument panel outlets.

(Bi-Level): Air is divided between the instrument panel and floor outlets.

(Floor): Air is directed to the floor outlets with some air directed to the side window outlets and windshield.

(Defog): This mode clears the windows of fog or moisture. Air directed to the floor and windshield outlets.

(Defrost): This modes clears the windshield of fog or frost more quickly. The system automatically controls the fan speed if AUTO mode is selected. If the outside temperature is 40°F (4°C) or warmer, the air conditioning compressor automatically runs to help dehumidify the air and dry the windshield. The air conditioning indicator light blinks three times if you try to turn off the compressor while in this mode.

(Outside Air): Press the right side of the button to turn the outside air mode on. An indicator light comes on to show that it is on. Air from outside the vehicle circulates throughout the vehicle. The outside air mode can be used with all modes, except the recirculation mode. Press again to cancel the recirculation mode.

(Recirculation): Press the left side of the button to turn the recirculation mode on. An indicator light above the button comes on to show that it is on. The air inside the vehicle is recirculated through the climate control system and throughout the vehicle, not from outside. This helps to limit the odors entering the vehicle and maximize air conditioning performance. The recirculation mode cannot be used while in defrost, defog, or floor mode. If recirculation is selected while in these modes, the indicator light flashes three times to let you know that it is not allowed. Use this mode only when it is needed for comfort, since window fogging occurs if the air conditioning compressor is not engaged. Press to cancel the auto recirculation feature. Each time the vehicle is started, the system reverts to the auto recirculation function. When the weather is cool or damp, operating the system in recirculation for extended periods of time can cause fogging of the vehicle's windows. To clear the fog, select either defog or defrost. Make sure the air conditioning is on.

(Air Conditioning): Press to turn the air conditioning on or off. A light above the button comes on while the air conditioning is on.

When air conditioning is selected or in AUTO mode, the system runs the air conditioning automatically to cool and dehumidify the air entering the vehicle.

On hot days, open the windows long enough to let hot inside air escape. This reduces the time it takes for the vehicle to cool down. Then keep the windows closed for the air conditioner to work its best.

On cool, but sunny days while using manual operation of the automatic system, use bi-level to deliver warm air to the floor and cooler air to the instrument panel outlets. To warm or cool the air, press or to the desired temperature setting.

In AUTO mode the system cools and dehumidifies the air inside the vehicle. Also, the system maximizes its performance by using recirculation as necessary.

Heating: On cold days when using manual operation of the automatic system, choose floor mode to deliver air to the floor outlets. To warm or cool the air delivered, adjust the temperature to the desired setting. To use the automatic mode, turn the knob to AUTO and adjust the temperature by pressing or .

Rear Window Defogger

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

(Rear): Press to turn the rear window defogger on or off. An indicator light above the button comes on to indicate that the rear window defogger is on.

If driving below 50 mph (80 km/h), the rear window defogger turns off about 15 minutes after the button is pressed. If turned on again, the defogger only runs for about seven and one-half minutes before turning off.

If the vehicle's speed is maintained above 50 mph (80 km/h), the rear window defogger remains on once the button is pressed.

If the vehicle has the remote start feature, the rear defogger automatically turns on if it is cold outside, but the indicator light does not come on. When the vehicle transitions out of remote start mode the rear defogger turns off.

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.