Mystery Switch
 

In my 2010 GLK350, there is a switch on the kick panel next to the hood release. It doesn’t seem to do anything when switched, but something may be happening that I am unaware of. Any idea what this is or what it is designed to do? It has two red wires running to it on the other side of the board that I have to remove when working behind the wheel.

https://cimg3.ibsrv.net/gimg/www.mbw...d65db4a2f.jpeg

There is a feature or requirement on European models to light up the left rear tail light for parking on unlit streets, that button may be part of that system, my 13 has a button on the dash for that purpose but it’s not connected. Turn it on at night and look at your left tail light.

That's definitely not a factory switch. Could really be for anything from a hard-wired radar detector, to aftermarket parking sensors, or to turn on some additional lighting somewhere. If you aren't able to tell what is functioning off of it, you'd have to trace those wires to wherever they're leading.

It's very close to one of the fuse panels, so one wire will be leading there and the other to whatever was added on.