GM Service Manual Online
For 1990-2009 cars only

With this system, you can control the heating, cooling, and ventilation in the vehicle. The vehicle also has a flow-through ventilation system described later in this section.


Object Number: 1734983  Size: B2

Different climate control settings can be selected for the driver and passengers.

Driver and Passenger Side Temperature Controls

The driver and passenger side temperature buttons 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.

Press the + or - buttons to increase or decrease the cabin temperature. The driver side or passenger side temperature display shows 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 illuminates and both the driver's side and passenger's 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 changes to show the current temperature(s) and AUTO is lit on the display. The current air delivery mode and fan speed are also displayed for about 5 seconds.

    When AUTO is selected, the air conditioning operation and air inlet are automatically controlled. The air conditioning compressor may run when the outside temperature is above freezing. The air inlet will normally be set to outside air. If it is hot outside, the air inlet may automatically switch to the recirculate mode to help quickly cool down the air inside 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'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.

Be careful not to cover the solar sensor located on the top of the instrument panel near the windshield. This sensor regulates air temperature based on sun load. 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 the fan on until warm air is available. The length of delay depends on the engine coolant temperature. Pressing the fan switch overrides this delay and changes 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 be selected once you have selected 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 illuminates briefly to show you the settings and then returns to 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

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

(Fan): The buttons with the fan symbols let you manually adjust the fan speed. Press to increase fan speed and to decrease fan speed. Pressing either fan button while the system is off turns the system on. Pressing either fan button while in automatic control places the fan under manual control. The fan setting remains displayed and the AUTO light turns off. The air delivery mode remains under automatic control.

(Mode): Press and to manually change the direction of the airflow in the vehicle. Repeatedly press either button until the desired mode appears on the display. Pressing either mode button while the system is off changes the air delivery mode without turning the system on. Pressing either mode button while in automatic control places the mode under manual control. The air delivery mode setting is displayed and the AUTO light turns off. The fan remains under automatic control.

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

(Bi-Level):  Air is directed partly 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): 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 will automatically select outside air.

(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 the vehicle. Recirculation may also help cool the air inside the vehicle more quickly once the temperature inside the vehicle is less than the outside temperature. 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 be turned off by pressing the outside air button, or by turning off the ignition.

(Outside Air): Press this button to turn on the outside air mode. When this mode is selected, air from outside the vehicle circulates throughout the vehicle. An indicator light on the button comes on to let you know that it is activated. The outside air mode can be used with all modes, but it cannot be used with the recirculation mode.

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 let you know that the air conditioning has been activated. Pressing this button when the outside temperature is too cool for air conditioning makes the air conditioning indicator flash three times and then 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 let you know 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 you might notice a small amount of water dripping underneath the vehicle while idling or after turning off the engine. This is normal.

Sensors


Object Number: 829326  Size: A2

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: 1847537  Size: A1

The interior temperature sensor, located in the headliner, measures the temperature of the air inside your 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 on the rearview mirror.

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 the windshield.

Use and to select the defog or defrost modes.

(Defog):  Press this button 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.

(Defrost): Press this button to remove fog or frost from the windshield more quickly. This mode directs a portion of the air to the windshield and side window vents and some to the floor vents. In this mode, the system will automatically force outside air into your vehicle. The recirculation mode cannot be selected while in the defrost mode. The air conditioning compressor will run automatically in this setting, unless the outside temperature is close to freezing. Do not drive the vehicle until all the windows are clear.

Rear Window Defogger

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

(Rear Window Defogger): If your vehicle has this feature, press this button to turn the defogger on or off. It automatically turns off several minutes after it has been activated. The defogger can also be turned off by turning the engine off. 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): 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. See Outside Power Mirrors .