laz81

I have the option to turn on fog lights in my car. But my car doesn't have fog lights.
Is this button used for anything else? It's a c300 2015

CO2010

That only activates your rear fog lamp. On U.S. cars only your left rear lamp lights up making it more visible for cars behind you.

laz81

Really only the left rear lamp.. Interesting and strange. Thanks for the reply CO2010

MB205

I tested this on my UK C300 against a window. When I pressed that button I found that the front headlights became brighter, like in between dipped beam and full beam.

Seems that there is a fog setting on the front lamps?

BenzC400

Here is a very good explanation of vehicle lighting in general and rear fog lamps specifically. I originally thought my right side rear fog lamp was broken until I found out that having a rear fog lamp only on the drivers side is common, so that the driver's side of the car is more easily identified in poor visibility conditions and so that the fog lamp is not confused with brake lights.

http://en.wikipedia.org/wiki/Automotive_lighting

Merlin1

Drove in fog this past winter in my UK C200 (LED) noticed the offside headlamp beam change shape when switch on fog lamp switch. In UK both rear fogs come on.

laz81

Thanks for the link c400. That makes sense. I'm going to test and see if it has any effects on the front lights. Last night I didn't notice any.