GM Service Manual Online
For 1990-2009 cars only

The heating, cooling, and ventilation for the vehicle can be controlled with this system. For vehicles with the remote start feature, the climate control system functions as part of the remote start feature. See Remote Keyless Entry (RKE) System Operation.

United States version shown, Canada version similar.


Object Number: 2042707  Size: G3
  1. Fan Control

  2. Temperature Control

  3. Air Delivery Mode Control

  4. Air Conditioning

  5. Outside Air

  6. Recirculation

  7. Rear Window Defogger

Automatic Operation

This climate control system automatically maintains the desired temperature inside the vehicle. Do not cover the sensor located on the top of the instrument panel near the windshield or the sensor grille below the climate control faceplate. These two sensors help regulate the inside air temperature.

AUTO (Automatic Fan): Turn the fan knob to AUTO for the system to automatically adjust the fan speed to reach the desired inside temperature.

Temperature Control: Select the desired cabin air temperature between 60-90°F (16-32°C). Choosing the coldest or warmest temperature setting does not cause the system to heat or cool any faster.

AUTO (Automatic Air Delivery Mode): Turn the air delivery mode knob to AUTO for the system to automatically control the direction of the airflow to help reach the desired inside temperature.

The system automatically controls the air inlet to supply the outside air or recirculated inside air needed to heat or cool the vehicle faster. The recirculation button indicator light is lit whenever the recirculation mode is on.

Press the outside air button to change to outside air. However, the recirculation mode may turn back on automatically.

In cold weather, if the fan and air delivery modes are in automatic, the system starts at lower fan speeds to avoid directing cold air into the vehicle until warmer air is available. The climate control system directs air to the floor, but may automatically change modes as the vehicle warms up to maintain the chosen temperature setting. The length of time needed to warm the interior depends on the outside temperature and inside temperature of the vehicle.

Manual Operation

(Fan Control): Turn clockwise or counterclockwise to increase or decrease the fan speed. To turn the fan off, turn the left knob to the position. In any setting other than off, the fan runs continuously with the ignition on. The fan must be turned on to run the air conditioning compressor. There will be some airflow noticeable from the various outlets when driving, even with the fan in the off position. To turn off the air completely, turn the fan to and select the recirculation button.

Temperature Control: Turn clockwise or counterclockwise to increase or decrease the temperature. Select the desired cabin air temperature between 60-90°F (16-32°C). Typically, the best setting is near 75°F (23°C). Choosing the coldest or warmest temperature setting does not cause the system to heat or cool any faster.

Air Delivery Mode Control: Turn clockwise or counterclockwise to change the current airflow mode.

Select from the following air delivery modes:

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

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

(Floor): Air is directed to the floor outlets with some air directed to the windshield. When this mode is selected, the system turns the recirculation mode off. Recirculation mode cannot be selected while in floor mode. This is to help prevent window fogging.

(Defog): This mode clears the windows of fog or moisture. Air is directed to the floor outlets, with some air directed to the windshield and side window outlets. In this mode, the system turns the recirculation mode off and runs the air conditioning compressor unless the outside air is at or below freezing. Recirculation mode cannot be selected while in defog mode. This helps prevent window fogging.

(Defrost): This mode removes fog or frost from the windshield more quickly. Air is directed to the windshield and the side window outlets. In this mode, the system turns the recirculation mode off automatically and runs the air conditioning compressor unless the outside air is at or below freezing. Recirculation mode cannot be selected while in defrost mode. This helps prevent window fogging. For best results, clear all snow and ice from the windshield before defrosting.

(Air Conditioning): Press to turn the air conditioning system on or off. An indicator light comes on to show that the air conditioning is on. The air conditioning can be selected in any mode as long as the fan is on and the outside temperature is above freezing. A flashing indicator light indicates that the air conditioning compressor is currently not available. On hot days, use the automatic fan and automatic air delivery mode settings and the vehicle will reach the desired temperature more quickly. The desired fan and air delivery mode settings can still be adjusted manually. Open the windows to let the hot inside air escape, then close them. This helps reduce the time it takes for the vehicle to cool down and 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.

(Outside Air): Press to turn the outside air mode on. An indicator light comes on to show that outside air is on. Air from outside the vehicle will circulate throughout the vehicle. The outside air mode can be used with all modes, but it cannot be used with the recirculation mode. Pressing this button will cancel the recirculation mode.

(Recirculation): Press to turn on the recirculation mode. An indicator light comes on to show that recirculation is on. This mode recirculates and helps to quickly cool or heat the air inside the vehicle. It can be used to prevent outside air and odors from entering the vehicle. Avoid using the recirculation mode during high periods of humidity and cool outside temperatures since this may result in increased window fogging. If window fogging is experienced, select the defrost mode. Recirculation mode is not available in floor, defog or defrost modes and will shut off automatically and change to outside air. If the button is selected in any of these modes, the indicator will flash. This helps prevent window fogging and moisture building up inside the vehicle.

Rear Window Defogger

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

The rear window defogger only works when the ignition is in ON/RUN.

(Rear Window Defogger): Press to turn the rear window defogger on or off. An indicator light on the button comes on to show that it is activated.

The rear window defogger stays on for approximately 10 minutes after the button is pressed, unless the ignition is turned to ACC/ACCESSORY or LOCK/OFF. If turned on again, the defogger only runs for approximately five minutes before turning off. At higher vehicle speeds, the defogger may stay on continuously. The defogger can also be turned off by turning off the engine.

For vehicles with the remote start feature, the rear defogger will automatically turn on when remote start is activated.

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.

Remote Start Climate Control Operation

For vehicles with the remote start feature and if it is activated, the climate control system heats and cools the inside of the vehicle using the modes that were set before the vehicle was turned off.

The heating, cooling, and ventilation for the vehicle can be controlled with this system.


Object Number: 2042741  Size: G3
  1. Fan Control

  2. Temperature Control

  3. Air Delivery Mode Control

  4. Normal Air Conditioning

  5. Hybrid Air Conditioning

  6. Recirculation

  7. Rear Window Defogger

Climate Control Influence on Hybrid Operation and Fuel Economy

To maximize your fuel economy, use the following settings (as indicated by the green marking):

    • Set the fan knob to AUTO.
    • Set the air delivery knob to AUTO.
    • Select an air temperature setting near 75°F (23°C).
    • Select the Hybrid A/C button, if A/C is required.

Avoid using these settings that may lead to fewer auto stops and to higher fuel consumption:

    • Manual fan speed operation.
    • Defrost mode. Only use this setting to clear the windows.
    • Extreme cold or hot air temperature settings, such as 60°F (16°C) or 90°F (32°C).
    • Normal air conditioning mode, if A/C is required.

Automatic Operation

This climate control system automatically maintains the desired temperature inside the vehicle.

Do not cover the sensor located on the top of the instrument panel near the windshield or the sensor grille below the climate control faceplate. These two sensors help regulate the inside air temperature.

AUTO (Automatic Fan): Turn the fan knob to AUTO for the system to automatically adjust the fan speed to reach the desired inside temperature.

Temperature Control: Select the desired air temperature between 60-90°F (16-32°C). Typically, the best setting is near 75°F (23°C). Choosing the coldest or warmest temperature setting does not cause the system to heat or cool any faster.

AUTO (Automatic Air Delivery Mode): Turn the air delivery mode knob to AUTO for the system to automatically control the direction of the airflow to help reach the desired inside temperature.

The system automatically controls the air inlet to supply the outside air or recirculated inside air needed to cool the vehicle faster. The indicator light on the recirculation button will be lit whenever the system changes to recirculation. Press the recirculation button to change to outside air. However, the recirculation mode may turn back on automatically.

In cold weather, if the fan and air delivery modes are in automatic, the system starts at lower fan speeds to avoid directing cold air into the vehicle until warmer air is available. The climate control system directs air to the floor, but may automatically change modes as the vehicle warms up to maintain the chosen temperature setting. The length of time needed to warm the interior depends on the outside temperature and inside temperature of the vehicle.

Manual Operation

It is best to use the automatic settings to maximize fuel economy.

(Fan Control): Turn clockwise or counterclockwise to increase or decrease the fan speed. To turn the fan off, turn the left knob to the position. In any setting other than off, the fan runs continuously with the ignition on. The fan must be turned on to run the air conditioning compressor. There will be some airflow noticeable from the various outlets when driving, even with the fan in the off position. This is to ensure some fresh air is always available in the vehicle. To turn off the air completely, turn the fan to and select the recirculation button.

Temperature Control: Turn clockwise or counterclockwise to increase or decrease the temperature. Typically, the best setting is near 75°F (23°C). Choosing the coldest or warmest temperature setting does not cause the system to heat or cool any faster.

Air Delivery Mode Control: Turn clockwise or counterclockwise to change the direction of the airflow inside the vehicle.

Select from the following air delivery modes:

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

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

(Floor): Air is directed to the floor outlets with some air directed to the windshield. When this mode is selected, the system turns the recirculation mode off. Recirculation mode cannot be selected while in floor mode. This is to help prevent window fogging.

(Defog): This mode clears the windows of fog or moisture. Air is directed to the floor outlets, with some air directed to the windshield and side window outlets. In this mode, the system turns the recirculation mode off and runs the air conditioning compressor unless the outside air is at or below freezing. Recirculation mode cannot be selected while in defog mode. This helps prevent window fogging.

(Defrost): This mode removes fog or frost from the windshield more quickly. Air is directed to the windshield, with some air directed to the side window outlets and the floor outlets. In this mode, the system turns the recirculation mode off automatically and runs the air conditioning compressor unless the outside air is at or below freezing. The recirculation mode cannot be selected while in defrost mode. This helps prevent window fogging and moisture building up inside the vehicle. In this mode, the climate control system prevents all automatic engine start/stop operations. This ensures the best defrost performance. For best results, clear all snow and ice from the windshield before defrosting.

(Normal Air Conditioning): Press to turn the air conditioning system on or off. An indicator light comes on to show that the air conditioning is on. Normal Air Conditioning (A/C) can be selected in any mode as long as the fan is on and the outside air temperature is above freezing. Normal A/C cannot be selected at the same time as Hybrid Air Conditioning (A/C). A flashing indicator light indicates that the air conditioning compressor is currently not available. When Normal A/C is selected, the climate control system prevents all automatic engine start/stop operations. This will ensure the cabin comfort is maintained. See "Air Conditioning and Automatic Engine Start/Stop" later in this section.

(Hybrid Air Conditioning): Press to turn the Hybrid A/C system on or off. An indicator light comes on to show that Hybrid A/C is on. Hybrid A/C can be selected in any mode, except defrost as long as the fan is on and the outside air temperature is above freezing. Hybrid A/C cannot be selected at the same time as the normal air conditioning. A flashing indicator light shows the air conditioning compressor is not available. The Hybrid A/C works to balance fuel economy and air conditioning comfort. When Hybrid A/C is used in warm weather, the vehicle gets better fuel economy by allowing more frequent start/stops. For additional cooling, select Normal A/C. See "Air Conditioning and Automatic Engine Start/Stop" later in this section.

(Recirculation): Press to toggle between the recirculation and outside air modes. The indicator light turns on when the recirculation mode is selected. This mode can be used to prevent outside air and odors from entering the vehicle or to help cool the air inside the vehicle more quickly. Avoid using the recirculation mode during high periods of humidity and cool outside temperatures since this may result in increased window fogging. If window fogging is experienced, select the defrost mode. Recirculation mode is not available in floor, defog or defrost modes. If the button is selected in these modes, the indicator will flash. This helps prevent window fogging and moisture building up inside the vehicle.

Rear Window Defogger

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

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

(Rear Window Defogger): Press to turn the rear window defogger on or off. An indicator light on the button comes on to show that it is activated.

The rear window defogger stays on for about 10 minutes if the vehicle remains at slower vehicle speeds or until the button is pressed, or unless the ignition is turned to ACC/ACCESSORY or LOCK/OFF. If turned on again, the defogger only runs for about five minutes before turning off again. At higher vehicle speeds, the defogger may stay on continuously. The defogger can also be turned off by turning off the ignition.

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.

Air Conditioning and Engine Start/Stop

On hot days, use the automatic fan and automatic air delivery mode settings and the vehicle will reach the desired temperature more quickly. The desired fan and air delivery mode settings can still be adjusted manually. Open the windows to let the hot inside air escape, then close them. This helps reduce the time it takes for the vehicle to cool down and helps the system to operate more efficiently.

When either the Normal A/C or Hybrid A/C modes are active, the air conditioning system removes moisture from the air, so a small amount of water may drip under the vehicle while idling or after turning off the engine. This is normal.

The use of Normal A/C causes the engine to keep running while the vehicle is at a complete stop to allow the climate control system to continue cooling.

The use of Hybrid A/C allows automatic engine start/stop operations while the vehicle is at a complete stop. The air conditioning compressor can not run when the engine is not running, resulting in reduced cooling performance. The climate control system may keep the engine running or restart the engine during a stop to continue cooling. Selecting the Normal A/C button forces the engine and air conditioning compressor to restart automatically. For more information about Engine Start/Stop operation, see Starting the Engine.