2007 Mercedes C-Class Owner's Manual - Page 171

Controls in detail Climate control i If you have switched on the defrost function using the P or 0 button, you cannot make any other settings. Air recirculation mode Switch to air recirculation mode to prevent unpleasant odors from entering the vehicle from the outside (e.g. before driving through a tunnel). This setting cuts off the intake of outside air and recirculates the air in the passenger compartment. Warning! Activating Press button , ( page 165). The indicator lamp on the button comes on. Deactivating Press button P or 0 ( page 165) again. The indicator lamp on the button goes out. Defrosting is turned off. i The air recirculation mode is activated automatically at high outside temperatures. The indicator lamp on button , is not lit when the air recirculation mode is automatically switched on. A quantity of outside air is added after approximately 30 minutes. i The cooling remains switched on. Windshield fogged on the outside G i Keep this setting selected only until the windshield is clear again. Switch the windshield wipers on ( page 51). If the automatic mode of the climate control is switched off: Turn air distribution control 4 to a or Y ( page 165). Fogged windows impair visibility, endangering you and others. If the windows begin to fog on the inside, switching off the air recirculation mode immediately should clear interior window fogging. If interior window fogging persists, make sure the air conditioning ( page 172) is activated, or press button P or 0. 170