GM Service Manual Online
For 1990-2009 cars only

With this system the heating, cooling and ventilation can be controlled on the vehicle. When the vehicle is first started and the climate control system is on, or if the climate control system has been turned on, the display shows the driver's temperature setting for five seconds. Then it shows the outside temperature.


Object Number: 2049001  Size: B2
  1. Driver and Passenger Side Temperature Controls

  2. Fan Control

  3. Display

  4. AUTO

  5. Power Button

  6. Recirculation

  7. Air Conditioning

  8. Defrost

  9. Air Delivery Mode Control

  10. Rear Window Defogger

Outside Air Temperature Display

A new outside temperature reading is displayed if the vehicle has been off for more than three hours. If the vehicle has been off for less than three hours, the old temperature reading may be displayed because underhood heat is affecting the true outside temperature. Underhood heat can also affect the outside temperature while the engine is running. It may also take several minutes of driving before the display updates to the actual outside temperature.

Automatic Operation

AUTO (Automatic): When automatic operation is active, the system controls the air delivery mode, fan speed, and temperature inside the vehicle.

Use the steps below to place the entire system in automatic mode:

  1. Press AUTO.
  2. When AUTO is selected, the air conditioning and air inlet are automatically controlled. The air conditioning compressor will run continuously when the outside temperature is over approximately 40°F (4°C). The air inlet will normally be set to outside air. If it is hot outside, the air inlet automatically changes to recirculate inside air to help quickly cool down the vehicle.

  3. Set the driver's and passenger's temperature.
  4. To find your comfort setting, start with a 72°F (22°C) temperature setting and allow about 20 minutes for the system to adjust. Turn the driver or passenger side temperature knob to adjust the temperature setting as necessary. If a temperature setting of 60°F (15°C) is chosen, the system will remain at the maximum cooling setting. If a temperature setting of 90°F (32°C) is chosen, the system remains at the maximum heat setting. Choosing either maximum setting may not cause the vehicle to heat or cool any faster.

Manual Operation

(Off): Press to turn off the entire climate control system. Outside air still enters the vehicle, and will be directed to the floor. The system turns on by pressing either AUTO, air delivery mode, fan control, or by adjusting either temperature knob.

Driver's Side Temperature Knob: Turn clockwise or counterclockwise to increase or decrease the temperature on the driver side of the vehicle. The display will show the temperature setting decreasing or increasing and an arrow pointing toward the driver. This knob can also adjust the passenger side temperature setting if the two are linked.

Passenger Side Temperature Knob: Turn clockwise or counterclockwise to increase or decrease the temperature on the passenger side of the vehicle. The display will show the temperature setting decreasing or increasing and an arrow pointing toward the passenger. The passenger temperature setting can be set to match and link to the driver's temperature setting by pressing and holding the AUTO button for three seconds. When adjusting the driver side temperature setting, the passenger side temperature setting will follow and both arrows will appear on the display. The passenger side temperature setting also resets and re-links to the driver side temperature setting if the vehicle has been off for more than three hours.

(Fan Control): Press the arrows to increase or decrease the fan speed. The display shows the selected fan speed and the driver side temperature setting for five seconds.

(Air Delivery Mode Control): Press to change the direction of the airflow in the vehicle. The air delivery modes will appear on the display as it is being adjusted. The display shows the selected air delivery mode and the driver temperature setting for five seconds. To change the current air delivery mode, select one of the following:

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

(Bi-Level): Air is divided between the instrument panel and floor outlets. Some air is directed toward the windshield and side window outlets. Cooler air is directed to the upper outlets and warmer air to the floor outlets.

(Floor): Air is directed to the floor outlets. Some air also comes out of the defroster and side window outlets. The recirculation button cannot be selected in floor mode.

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

(Front Defrost): Press the front defrost button to clear the windows of fog or frost more quickly. The system automatically controls the fan speed if defrost is selected from AUTO mode. If the outside temperature is 40°F (4°C) or warmer, the air conditioning compressor runs automatically to help dehumidify the air and dry the windshield. Do not drive the vehicle until all the windows are clear.

A/C (Air Conditioning): Press to turn the air conditioning system on or off. When the system is on, the system automatically begins to cool and dehumidify the air inside of the vehicle. The air conditioning symbol appears on the display when the air conditioning is on and turns off when the air conditioning is off. If the air conditioning is turned off while in front defrost or defog mode, the air conditioning symbol turns off, however, the A/C compressor remains on to help de-humidify the air inside the vehicle. If one of the other modes is selected, the compressor will then turn the A/C off until it is selected again or the AUTO button is pressed. To avoid fogging the inside glass on rainy and humid days at a temperature above freezing, press the air conditioning button to run the A/C compressor. Also it is best to avoid the use of the recirculation mode except when maximum air conditioning performance is needed or for short times to avoid exterior odors. You may notice a slight change in engine performance when the air-conditioning compressor shuts off and turns on again. This is normal.

(Recirculation): Press to turn the recirculation mode on or off. An indicator light comes on to show that recirculation is on. This mode recirculates and helps to quickly cool the air inside the vehicle. It can be used to help prevent outside air and odors from entering the vehicle. Recirculation mode can be used with vent and bi-level modes, but it cannot be used with floor, defog or defrost modes. If recirculation mode is selected with floor, defog, or defrost modes, the indicator flashes three times and turns off to indicate the selection is not available. The air conditioning compressor may also run while in recirculation mode. This is normal and helps to prevent window fogging. If the weather is cold and damp, the system may cause the windows to fog while using recirculation mode. If the windows do start to fog, select defog or defrost mode and increase fan speed. Recirculation mode, if selected, will be cleared when the engine is turned off.

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 comes on to show that the rear window defogger is on.

The rear window defogger will turn off approximately 10  minutes after the button is pressed. If additional warming time is needed, press the button again.

The heated mirrors will also come on when the rear window defogger is turned on. See Outside Heated Mirrors.

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.