2006 Mercedes S-Class Owner's Manual - Page 202

Controls in detail Automatic climate control The system automatically switches to the air recirculation mode if the carbon monoxide (CO) or nitrogen oxide (NOX) concentration of the outside air increases beyond a predetermined level, for example in a tunnel. The automatic air recirculation mode does not function if ± is selected or if the outside temperature has fallen below 41°F (5°C). The activated charcoal filter should be switched off when windows fog up on the inside, or if the passenger compartment needs to be quickly heated or cooled down. Rear window defroster The rear window defroster uses a large amount of power. To keep battery drain to a minimum, switch off the defroster as soon as the rear window is clear. The defroster is automatically deactivated after approximately 6 to 17 minutes of operation depending on the outside temperature. Activating Press button F ( page 193). The indicator lamp on the button comes on. Deactivating Press button F ( page 193) again. The indicator lamp on the button goes out. Warning! ! If the rear window defroster switches off too soon and the indicator lamp starts flashing, this means that too many electrical consumers are operating simultaneously and there is insufficient voltage in the battery. The system responds automatically by deactivating the rear window defroster. As soon as the battery has sufficient voltage, the rear window defroster automatically turns itself back on. G Any accumulation of snow and ice should be removed from the rear window before driving. Visibility could otherwise be impaired, endangering you and others. 201