GM Service Manual Online
For 1990-2009 cars only

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


Object Number: 1689828  Size: B2

Different temperature settings can be selected for the driver and all passengers.

Display Function

Each time the temperature, mode, or fan control buttons are pressed, the climate control display shows that function along with the inside temperature setting. The outside temperature is displayed on the instrument panel cluster.

Driver's Side Temperature Control

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

Press the + or - buttons to increase or decrease the temperature. The driver side temperature display will show the temperature setting decreasing or increasing.

Passenger's Side Temperature Control

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

Press the + or - buttons to increase or decrease the temperature. The passenger side display will show the temperature setting decreasing or increasing.

The passenger's temperature setting can be set to match the driver's temperature setting by pressing the PASS button and turning off the PASS indicator. When the passenger's temperature setting is set different than the driver's setting, the indicator on the PASS button comes on and both the driver side and passenger side temperature displays are shown.

Automatic Operation

AUTO (Automatic): When automatic operation is active the system controls 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 shows the current temperature(s) selected and AUTO is on the display. The current delivery mode and fan speed also display for approximately 5 seconds.

    When AUTO is selected, the air conditioning operation and air inlet are 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 your vehicle. The light comes on the recirculation button while in recirculation.

  3. Set the driver's and passenger's temperature.
  4. To find your comfort setting, start with a 73°F (22°C) temperature setting and allow about 20 minutes for the system to regulate. Use the driver's or passenger's temperature buttons to adjust the temperature setting as necessary. If you choose the temperature setting of 60°F (15°C), the system remains at the maximum cooling setting. If you choose the temperature setting of 90°F (32°C), 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 cover the solar 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 your vehicle's headlamps. For more information on the solar sensor, see "Sensors" later in this section.

To avoid blowing cold air 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. Press the fan switch to override this delay and change the fan to a selected speed.

(On/Off): Press this button to turn off the climate control system. Outside air still enters the vehicle, and is directed to the floor. This direction can be changed by pressing the mode button. Recirculation can only be selected in vent or bi-level mode. The temperature can also be adjusted using either temperature button. If you adjust the air delivery mode or temperature settings with the system off, the display comes on briefly to show the settings and then turns off. Press the on/off button or the up down arrows on the fan switch, the defrost button, AUTO button, or the air conditioning button to turn the system on when it is off.

Manual Operation

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

(Fan): The buttons with the fan symbols let you manually adjust the fan speed. Press the up arrow to increase fan speed and the down arrow to decrease fan speed. Pressing a fan button while the system is off will turn the system on. Pressing a fan button while in automatic control places the fan under manual control. The fan setting remains displayed, the word AUTO is no longer displayed, and the AUTO button indicator light turns off. The air delivery mode remains in automatic control.

(Mode): Press the mode up and down buttons to manually change the direction of the airflow in the vehicle. Repeatedly press the button until the desired mode appears on the display. Pressing a mode button while the system is off will change air delivery mode without turning the system on. Pressing one of these buttons while in automatic control to place the mode under manual control. The air delivery mode setting remains displayed, the word AUTO is no longer displayed, and the AUTO button indicator light turns off.

(Vent): This setting delivers air to the instrument panel outlets.

(Bi-Level):  This mode directs air to the instrument panel outlets and to the floor outlets. A little air is directed towards the windshield and side window outlets. 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 of the air directed to the windshield, side window outlets, and second row floor outlets. In this mode, the system automatically selects outside air. Recirculation cannot be selected in floor mode.

(Defog): See "Defogging and Defrosting" later in this section.

(Recirculation): Press this button to turn the recirculation mode on. When the button is pressed, an indicator light comes on. This mode keeps outside air from entering the vehicle. It can be used to reduce outside air and prevent odors from entering your vehicle. Recirculation also helps to quickly cool the warmer air inside your vehicle. The recirculation mode cannot be used with floor, defrost, or defogging modes. If you try to select recirculation in one of those modes, the indicator flashes three times and 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. Press the button again to turn off the recirculation mode. It automatically turns off when the engine is turned off and must be re-selected when the engine is turned on again.

Air Conditioning

(Air Conditioning): Press this button to turn the air conditioning (A/C) compressor on and off. When air conditioning is selected, an indicator light comes on to show that the air conditioning has been activated. The air conditioning compressor does not work when outside temperatures fall below 40°F (4°C). Pressing this button when the outside temperature is too cool makes the air conditioning indicator flash three times and turn off to let you know 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 may drip underneath your vehicle while idling or after turning off the engine. This is normal.

Sensors


Object Number: 1831307  Size: B3

The solar sensor, located in the defrost grille in the middle of the instrument panel, monitors the solar radiation. Do not cover the solar sensor or the system will not work properly.


Object Number: 1831311  Size: B3

The interior temperature sensor located on the instrument panel to the right of the steering column, measures the temperature of the air inside the vehicle.

There is also an exterior temperature sensor located behind the front grille. This sensor reads the outside air temperature and helps maintain the temperature inside the vehicle. Any cover on the front of the vehicle could cause a false reading in the displayed temperature.

The climate control system uses the information from these sensors to maintain your comfort setting by adjusting the outlet temperature, fan speed, and the air delivery mode. The system may also supply cooler air to the side of the vehicle facing the sun. The recirculation mode will also be used as needed to maintain cool outlet temperatures.

Defogging and Defrosting

Fog on the inside of the 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 or frost from your windshield.

Use the mode up and down arrows to select the defog mode. Use the defrost button to select the defrost mode.

(Defog):  The defog mode is used to clear the windows of fog or moisture and warm the passengers. This mode directs air to the windshield, floor outlets, and side window vents. When this mode is selected, 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. Do not drive the vehicle until all the windows are clear. To clear fog from the rear seat side windows, select the bi-level mode on the rear climate control system and direct the headliner outlets toward the side windows.

(Defrost): Press this button to remove fog or frost from the windshield more quickly. This mode directs most of the air to the windshield and side window vents and some to the floor vents. In this mode, the system automatically forces outside air into the vehicle. The recirculation mode cannot be selected while in the defrost mode. The air conditioning compressor runs automatically in this setting, unless the outside temperature is close to freezing. Do not drive the vehicle until all the windows are clear. While in defrost mode, if the PASS button is pressed, the PASS button indicator will flash three times to let you know that the passenger climate control system cannot be activated. If the passenger temperature buttons are adjusted while in defrost mode, the driver temperature indicator will change. The passenger temperature will not be displayed.

AUX (Auxiliary): Press this button to turn the rear heating and air conditioning on. See Rear Air Conditioning and Heating System or Rear Air Conditioning and Heating System and Electronic Climate Controls .

Rear Window Defogger

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

(Rear Window Defogger): Press this button to turn the rear window defogger on or off. The rear window defogger stays on for about 10 minutes after the button is pressed, before turning off. The defogger can also be turned off by pressing the button again or by turning off the engine. Do not drive the vehicle until all the windows are clear.

If your vehicle has heated outside rearview mirrors, the mirrors will heat to help clear fog or frost from the surface of the mirror when the rear window defog 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.