GM Service Manual Online
For 1990-2009 cars only

The heating, cooling, and ventilation in the vehicle can be controlled with this system. The vehicle also has a flow-through ventilation system described later in this section.

Climate Control with Heated and Cooled Seats shown


Object Number: 2047667  Size: B2
  1. Driver and Passenger Temperature Controls

  2. AUTO

  3. Recirculation

  4. Air Conditioning

  5. Heated and Cooled Seats

  6. Fan Control

  7. Defrost

  8. Rear Window Defogger

  9. Air Delivery Mode Control

(Off): Press the driver side temperature knob to turn the climate control system off. Outside air still enters the vehicle, and is directed to the floor. This direction can be changed by pressing the mode button. The temperature can also be adjusted using either temperature knob. Press the up or down arrows on the fan switch, the defrost button, the AUTO button, driver side temperature knob, or the air conditioning button to turn the system on when it is off.

Driver and Passenger Side Temperature Knob

The driver and passenger side temperature knobs are used to adjust the temperature of the air coming through the system on the driver or passenger's side of the vehicle. The temperature can be adjusted even if the system is turned off. This is possible since outside air always flows through the system as the vehicle is moving forward unless it is set to recirculation mode. See "Recirculation" later in this section.

Turn the knob clockwise or counterclockwise to increase or decrease the cabin temperature. The display will show the temperature setting increasing or decreasing.

Set the passenger's temperature setting to match the driver temperature setting by pressing the passenger power knob.

Automatic Operation

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

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

  1. Press the AUTO button.
  2. When AUTO is selected, the display will change to show the current temperature(s) and AUTO will appear. The current delivery mode and fan speed will also be displayed for approximately five seconds.

    When AUTO is selected, the air conditioning operation and air inlet will be automatically controlled. The air conditioning compressor will run when the outside temperature is over about 40°F (4°C). The air inlet will normally be set to outside air. If it is hot outside, the air inlet may automatically switch to recirculate inside air to help quickly cool down the vehicle. The light on the button comes on in recirculation.

  3. Set the driver's and passenger's temperature.
  4. To find your comfort setting, start with a 74°F (23°C) temperature setting and allow about 20 minutes for the system to regulate. Use the driver or passenger temperature buttons to adjust the temperature setting as necessary. If a temperature setting of 60°F (15°C) is chosen, the system remains 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 will not cause the vehicle to heat or cool any faster.

Do 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.

To avoid blowing cold air in cold weather, the system will delay turning on the fan until warm air is available. The length of delay depends on the engine coolant temperature. Pressing the fan switch will override this delay and change the fan to a selected speed.

Manual Operation

You may manually adjust the air delivery mode or fan speed.

(Fan Control): Press the up or down arrows to increase or decrease the fan speed Pressing this button when the system is off will turn the system on. Pressing either arrow while using automatic operation will place the fan in manual operation. The fan setting will display and the AUTO light will turn off. The air delivery will remain in automatic operation.

(Air Delivery Mode Control): Press to change the direction of the airflow in the vehicle. Repeatedly press the button until the desired mode appears on the display. When the system is turned off, the display goes blank after displaying the current status of the system.

(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 towards the windshield and side window outlets. Cooler air is directed to the upper vents and warmer air to the floor vents.

(Floor): Air is directed to the floor outlets, with some to the windshield, side window outlets, and second row floor outlets. In this mode, the system automatically selects outside air.

(Defog):  This mode clears the windows of fog or moisture. Air is directed to the windshield, floor outlets, and side window vents. In this mode, the system turns off recirculation and runs the air conditioning compressor unless the outside temperature is close to freezing. The recirculation mode cannot be selected while in the defog mode.

(Defrost): This mode removes fog or frost from the windshield more quickly. Air is directed to the windshield and side window vents, with some directed to the floor vents. In this mode, the system automatically forces outside air into the vehicle and runs the air conditioning compressor unless the outside temperature is close to freezing. The recirculation mode cannot be selected while in the defrost mode. Do not drive the vehicle until all the windows are clear.

(Air Conditioning): Press to turn the air conditioning (A/C) compressor on and off. An indicator light comes on to show that the air conditioning is on. Pressing this button when the outside temperature is too cool for air conditioning will make the air conditioning indicator flash three times and then turn off indicating the air conditioning mode is not available. If the air conditioning is on and the outside temperature drops below a temperature which is too cool for air conditioning to be effective, the air conditioning light turns off to show that the air conditioning mode has been canceled. On hot days, open the windows long enough to let hot inside air escape. This helps to reduce the time it takes for the vehicle to cool down. It also helps the system to operate more efficiently. The air conditioning system removes moisture from the air, so a small amount of water might drip under the vehicle while idling or after turning off the engine. This is normal.

(Recirculation): Press to turn the recirculation mode on or off. An indicator light comes on to show that the 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. The recirculation mode cannot be used with floor, defog, or defrost modes. If recirculation is selected with one of those modes, the indicator light flashes three times and then turns off. The air conditioning compressor also comes on when this mode is activated. While in recirculation mode the windows may fog when the weather is cold and damp. To clear the fog, select either the defog or defrost mode and increase the fan speed. The recirculation mode can also be turned off by turning off the ignition.

Rear Window Defogger

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

(Rear Window Defogger): Press to turn the rear window defogger on or off. It automatically turns off after it has been activated. The defogger can also be turned off by turning off the engine. Do not drive the vehicle until all the windows are clear.

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.

Heated Mirrors: For vehicles with heated outside rearview mirrors, the mirrors heat to help clear fog or frost from the surface of the mirror when the rear window defog button is pressed. See Outside Heated Mirrors.

Heated or Cooled Seats: For vehicles with heated seats or heated and cooled seats, see Heated Seats or Heated and Cooled Seats.