2008 Cadillac CTS Owner's Manual - Page 163

DC (Fan): Press the D or C buttons to increase or decrease the fan speed. Pressing either button cancels automatic operation and the system goes into manual mode. Press AUTO to return to automatic operation. The blower may reduce during an Onstar® session to limit background noise. If the airflow seems low when the fan speed is at the highest setting, the passenger compartment air filter might need to be replaced. For more information, see Passenger Compartment Air Filter on page 3-28 and Scheduled Maintenance on page 6-4. M / F (Recirculation/Outside Air): Press this button to switch between recirculation and outside air. Whenever the button is pressed, the indicator light comes on for the mode being used. The recirculation mode recirculates air inside the vehicle. It can be used to prevent outside air and odors from entering the vehicle or to help cool the air inside the vehicle more quickly. Press the auto button to have the system select the best air delivery mode for your temperature setting. Recirculation is not available in the defrost mode and automatically turns off 10 minutes after defog is selected. This helps to limit window fogging in the vehicle. Using recirculation for long periods of time could cause the air inside the vehicle to become too dry or stuffy. To prevent this from happening, after the air in the vehicle has cooled, select outside air or press the auto button. The outside air mode pulls fresh air from outside the vehicle. Outside air is always selected in defrost mode to prevent fogging. # (Air Conditioning): Press this button to override the automatic system and turn the air conditioning system on or off. When in AUTO, the air conditioning compressor will come on automatically, as necessary. The air conditioning system removes moisture from the air, so a small amount of water might drip underneath the vehicle while idling or after turning off the engine. This is normal. _ (Heated Windshield Washer, If Equipped): For more information, see Windshield Washer on page 3-11. 3-25