Interesting switch...

[Rooster]

So yesterday I'm investigating my fog light issue and I noticed a small microswitch in the fuse area. I flip the switch and the NAV unit screen goes blank. I still have radio and all the buttons work (vol/seek/etc) but absolutely no screen. I tried popping a DVD into either the NAV unit or the DVD player in the center console, no video thinking its an override to watch DVD's up front, nope. I'm clueless as to why some one would wire up a switch this way. Any ideas..?