To de-activate your interior lighting: when the interior lights are ON...press and hold the interior light button (the larger button up by the mirror) for 3 or more seconds. The lights will turn OFF, and will not turn ON when the doors are opened...I can't say what that does to the welcome lighting. To re-activate your interior lighting...just press the interior light button. The lights will turn ON, and they will now turn ON whenever you open your doors.

I had the dealer remove my from interior light because it was sooo bright. This is the large light by the rearview mirror. I had done this on my other 5-series and loved it. This way, you still get some interior lighting, but it doesn't blind you (the driver) when it comes ON.