CrazyOneToo - regarding the ignition switch - the fact that you are not having any ignition problems is (mostly) irrelevant. Apparently the wiring that goes through the ignition switch is complex and can affect multiple different modules beyond just activating the starter. I don't know the wiring diagram specifics, but there are lots and lots of case reports of ignition switches causing all sorts of unusual symptoms - all the while the starting of the car was unaffected. The posting that I linked is just one of many, and the list of "gremlin effects" is remarkably varied.
So it's a wild guess, but a somewhat educated one. Your car and your decision, but I wouldn't dismiss it out of hand just because the car is starting fine.
You make reference to the general module. Not sure if that is the issue (the bmwgm5 website makes no reference to headlights or hazard flashers), but perhaps get in touch with Scott at
www.bmwgm5.com. The web site talks about how to get in touch with him. I can add to the other testimonials and say he did a great job many years ago replacing some of the relays in the e53 that is now driven by one of my sons. He knows a lot about the module and I'm sure his opinion would be valuable. Anyway, best of luck.