GM Service Manual Online
For 1990-2009 cars only

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


Object Number: 1734983  Size: B2

You can select different climate control settings for the driver and passengers.

Driver's Side Temperature Control

The driver's side temperature buttons are used to adjust the temperature of the air coming through the system on the driver's 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 cabin 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's 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 cabin 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 will illuminate and both the driver's side and passenger's side temperature displays will be shown.

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 be lit on the display. The current delivery mode and fan speed will also be displayed for approximately 5 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 your vehicle. The light on the button will illuminate 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 will remain at the maximum cooling setting. If you choose the temperature setting of 90°F (32°C), the system will remain 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 and also turns on your headlamps. For more information on the solar sensor, see "Sensors" later in this section.

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.

(On/Off): Press this button to turn off the climate control system. Outside air will still enter the vehicle, and will be 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 will illuminate briefly to show you the settings and then return 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 may manually adjust the air delivery mode or fan speed.

(Fan): The buttons with the fan symbols allow you to manually adjust the fan speed. Press the up arrow to increase fan speed and the down arrow to decrease fan speed. Pressing one of these buttons when the system is off will turn the system on. Pressing one of these buttons when in automatic control will place the fan under manual control. The fan setting will remain displayed and the AUTO light will turn off. The air delivery mode will remain under automatic control.

(Mode): Press the mode up and down buttons to manually change the direction of the airflow in your vehicle. Repeatedly press the button until the desired mode appears on the display. Pressing one of these buttons when the system is off will change air delivery mode without turning the system on. Pressing one of these buttons when in automatic control will place the mode under manual control. The air delivery mode setting will be displayed and the AUTO light will turn off. The fan will remain under automatic control.

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

(Bi-Level):  This mode directs half of the air to the instrument panel outlets and to the floor outlets. The flow can be divided between vent and floor outlets depending upon where the knob is placed between the settings. 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 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 will come 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 may also help cool the air inside your vehicle more quickly once the temperature inside the vehicle is less than the outside temperature. 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 will flash three times and turn off. The air conditioning compressor will also come 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. Recirculation mode can be turned off by pressing the button again, or turning off the engine.

(Outside Air): Press this button to turn on the outside air mode. When this mode is selected, air from outside the vehicle will circulate throughout your vehicle. An indicator light on the button will come 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. Pressing this button again will cancel 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 will come 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 will make 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 will turn 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 your vehicle to cool down. It also helps the system to operate more efficiently.

The air conditioning system removes moisture from the air, so you may sometimes notice a small amount of water dripping underneath your 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, middle of the instrument panel, monitors the solar radiation. Do not cover the solar sensor or the system will not work properly.


Object Number: 1620180  Size: A3

There is also an interior temperature sensor located next to the steering wheel that 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.

In order to prevent false temperature readings at startup, the displayed temperature will not change until the following occurs:

    • Vehicle speed is above 10 mph (16 kmh) for 5 minutes.
    • Vehicle speed is above 32 mph (51 kmh) for 2 and a half minutes.

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 or defrost modes.

(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 you select 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. 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): Press this button to turn on the rear window defogger. It will automatically turn off several minutes after it has been activated. 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.