I just had to fix my lights again, my original fix didn't last even 6 months. This time instead of using a soldering iron to heat up the solder joints, I just used a heat gun aimed at the board, and "refreshed" all the solder connections at once. This was way faster (took about a minute) and has fixed everything that was not working. I'll see how long the fix lasts this time, but so far I think this is a much better method than reheating with a soldering iron.
2003 325xi Black³