2005 Cadillac STS Owner's Manual - Page 181

yAz (Fan): Press this switch to increase or decrease the fan speed. Pressing this switch cancels automatic operation and allows the operator to manually select the amount of airflow. Press AUTO to return to automatic operation. If the airflow seems low when the fan speed is at the highest setting, the passenger compartment air filter may need to be replaced. For more information, see Passenger Compartment Air Filter on page 3-54 and Scheduled Maintenance on page 6-4. In some conditions, using recirculation for long periods of time may cause the air inside your vehicle to become too dry or stuffy. To prevent this from happening, after the air in your vehicle has cooled, select AUTO to return to automatic climate control operation or push the recirculation button again to select outside air. Pressing this button a second time selects outside air. : (Outside Air): h (Recirculation): This button controls the air source for the climate control system. If you are in AUTO mode, pressing this button once will choose recirculation. This mode keeps outside air from coming in the vehicle and recirculates the air in the vehicle. It can be used to prevent outside air and odors from entering your vehicle or to help cool the air inside your vehicle more quickly. Recirculation is not available in the defrost mode and will shut off when defog mode is selected. Both of these features are designed to limit fogging in your vehicle. If recirculation is selected during defog mode, it will automatically turn off after 10 minutes to limit problems with fogging. This mode forces the system to pull air from outside the vehicle. It can be used to bring fresh air into the vehicle. Air Quality Sensor: Your vehicle may be equipped with an optional air quality sensor to help limit the climate control system from pulling in some harmful exhaust fumes from older, poorly running or diesel-equipped vehicles that are driving near you. This sensor, when active, will monitor the air quality in front of your vehicle and switch to air recirculation when poor quality air is detected outside your vehicle. You can activate the air quality sensor on your vehicle (if equipped) by pressing the AUTO button on your climate control. The word AUTO will be shown in the center of the climate control display under the outline shape of a vehicle. When the air quality sensor senses poor quality air, the recirculation graphic will be shown as long as the sensor senses poor quality air. 3-49