Well thanks for all of the suggestions if nothing else I have learned that its not OEM and had few laughs. I will just have to trace the wires this weekend and see where they go. I will post back in this thread and let you guys know what the hell this button controls.
Would be funny if it did kill the rear plate lamps.
2007 335i sport sedan fully loaded
2002 Z06 electron blue, custom cam, ect....
2008 Tahoe LTZ fully loaded