Originally Posted by marksae
I guess this is a semi-common problem that will start creeping up as our cars get older. I did a quick google search and found postings of this issue across several different E90 forums. I hope the replacement parts have this corrosion issue resolved!
I have always suspected that LED light enclosures were prone to this. I can't tell you how many cars of ALL makes are driving around with banks of lights out.
LEDs usually have their lifespans rated in 10s of thousands of hours. While you MIGHT have a few premature failures, seeing stips of lights/half of the tail light out means something is going wrong with the wiring. Corrosion makes sense. The good news is that BMW couldn't be charging much more than a few grand for a set of replacment lights, right?