2004 Mercedes SL-Class Owner's Manual - Page 177

Controls in detail Automatic climate control i Deactivating Press button , ( page 171). The indicator lamp on the button goes out. If you keep button , pressed, the side windows will close. The air recirculation mode is activated automatically at high outside temperatures if the concentration of carbon monoxide and nitrogen oxide in the outside air increases, for example in a tunnel If you have turned off the air conditioner ( page 179) or the outside temperature is below 41°F (5°C), the air recirculation mode will not switch on automatically. after five minutes if the air conditioner is turned off after 30 minutes if the outside temperature is above approximately 41°F (5°C) At outside temperatures above 79°F (26°C) the system will not automatically switch back to outside air. A quantity of outside air is added after approximately 30 minutes. i If you keep button , pressed, the side windows will return to their previous position. The air recirculation mode is deactivated automatically after five minutes if the outside temperature is below approximately 41°F (5°C) 176