GM Service Manual Online
For 1990-2009 cars only

With this system you can control the heating, cooling and ventilation for your vehicle.


Object Number: 1235822  Size: B2

Operation

To change the current mode, use the right knob to select one of the following:

(Vent): This mode directs air to the instrument panel outlets.

(Bi-Level): This mode directs air to the instrument panel outlets and to the floor 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 air directed to the windshield. When you select this mode, the system will turn recirculation mode off automatically and will run the air conditioning compressor unless the outside air is at or below freezing. Recirculation mode cannot be selected while in floor mode. This is designed to limit fogging in your vehicle.

The right knob can also be used to select defog or defrost mode. See "Defogging and Defrosting" later in this section.

(Fan): Turn the center knob clockwise or counterclockwise to increase or decrease the fan speed. To turn the fan off, turn the center knob all the way counterclockwise. In any setting other than off, the fan will run continuously with the ignition on. The fan must be turned on to run the air conditioning compressor.

Temperature Control: Turn the left knob clockwise or counterclockwise to increase or decrease the temperature inside your vehicle.

(Recirculate): This mode keeps outside air from coming in the vehicle. It can be used to prevent outside air and odors from entering your vehicle or to help heat or cool the air inside your vehicle more quickly. An indicator light will come on in this mode. Operation in this mode during periods of high humidity and cool outside temperatures 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 until a mode other than floor, defog or defrost is selected. This is designed to limit fogging in your vehicle.

(Air Conditioning): Press this button to turn the air conditioning system on or off. When this button is pressed, an indicator light above the button will come on to let you know the air conditioning is activated. Air conditioning can be selected in any mode as long as the fan switch is on.

On hot days, open the windows to let hot inside air escape; then close them. 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.

Defogging and Defrosting

Fog on the inside of 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 and side windows. Use the defog mode to clear the windows of fog or moisture and warm the passengers. Use the defrost mode to remove fog or frost from the windshield more quickly. For best results, clear all snow and ice from the windshield before defrosting.

Turn the right knob to select the defog or defrost mode.

(Defog): This mode directs air to the windshield, side window outlets and floor outlets. When you select this mode, the system will turn recirculation mode off automatically and will run the air conditioning compressor unless the outside air is at or below freezing. Recirculation mode cannot be selected while in defog mode. To defog the windows faster, turn the temperature knob clockwise to the warmest setting.

(Defrost): This mode directs most of the air to the windshield, with some air directed to the side window outlets and the floor outlets. When you select this mode, the system will turn recirculation mode off automatically and will run the air conditioning compressor unless the outside air is at or below freezing. Recirculation mode cannot be selected while in defrost mode. To defrost the windows faster, turn the temperature knob clockwise to the warmest setting.

Operation Tips

After the front window is clear of ice or fog, operating in the mixing mode between bi-level and floor will help clear the side windows. To do this, do the following:

    • Change the mode to a setting between floor mode and bi-level mode.
    • Aim the outboard panel registers toward the side windows.
    • Close the inboard panel registers.
    • Operate at blower two or three.
    • Adjust the temperature knob for best comfort.

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 RUN.

(Rear Window Defogger): Press the button to turn the rear window defogger on or off. An indicator light above the button will come on to let you know that the rear window defogger is activated.

The rear window defogger will stay on for approximately 15 minutes after the button is pressed, unless the ignition is turned to ACC or LOCK. If turned on again, the defogger will only run for approximately five minutes before turning off. The defogger can also be turned off by pressing the button again or by turning off the engine.

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.