Originally Posted by
BavarianZHP
Hm, it should work if you already have an auto-dimming mirror. All EXX series BMW's use the same mirror connections I think. I didn't have an auto-dimming mirror so I had to wire in pins 3 (12V) and 10 (Ground) to get the auto-dimming and compass functions to work. If you have a voltmeter I'd check out those pins on your connector.
Did the mirror's security light blink at least? If you fail to re-wire and need it, the clown nose should still blink (pins 8 and 9 are on all mirrors and BMWs) but the compass and auto-dimming won't work.
If you have an SOS equipped car and don't do the re-wiring, it will brick the mirror - so if you had that feature on your old mirror, that could well have been the cause.