BMW M4 Light System Goes Haywire, Switch Malfunction?

Had the same nightmare with my 2020 BMW M2 Competition last month. Light switch was acting up just like yours, complete lighting chaos. Turns out the connector pins in the light control module were corroded and making poor contact. Took it to the dealership since this needed proper diagnostic equipment. The technician showed me the issue, some pins had slight oxidation and weren't making proper contact. They cleaned the connections, applied dielectric grease, and double-checked all the wiring harness connections. Not a major repair, but definitely needed expert hands with the right tools. My lights have been working perfectly since then. With these newer BMWs, electrical gremlins usually come down to connection issues rather than the actual switch being faulty. Worth getting it checked at an authorized dealer since they have the right diagnostic tools for these specific problems.

Hey, thanks for sharing your experience! That's super helpful to know about the corroded pins, sounds exactly like what's happening with my M4. The dealer diagnosis makes total sense given how complex these systems are. Would you mind sharing what the repair cost you? Also, have you had any other electrical quirks pop up since they fixed it? Just want to make sure I'm prepared in case there's more to it than just the connector issue.

Hey there! Happy to follow up about my M2 Competition's light switch saga. After I took it to the mechanic last month, they found and fixed the faulty light switch, it was indeed just a bad cable/plug connection like I suspected. The whole thing set me back 95€, which wasn't too bad considering all the drama it was causing! Since the repair, my lighting system has been working perfectly, no more unusual light shows or electrical gremlins to speak of. What they found was actually a bit different from what they initially thought with the corroded pins. It turned out to be a simpler fix with just a loose connection that needed sorting. I'm really glad I got it done properly rather than trying any DIY solutions. The car's been running like a dream since then, no other electrical issues whatsoever. You're definitely making the right call getting yours checked out. These modern BMWs can be pretty sensitive when it comes to their electronics, but once you get the problem sorted, they're solid as a rock. Let me know how you get on with yours!

Thanks for the detailed follow-up! I actually just got back from getting my M4 checked out. Followed your advice and took it to a certified mechanic. Funny enough, my issue was similar but slightly different, turned out the main connector had worked itself loose after hitting a few bumps. The repair was surprisingly quick and affordable, only took them about an hour and cost less than I expected. The mechanic showed me exactly what was wrong, which I really appreciated. No fancy tools needed in the end, just needed someone who knew what they were looking at. Been driving for a few days now and everything's working perfectly, no more unusual light shows! Such a relief to have it sorted. Really glad I didn't try to fiddle with it myself. Sometimes the simplest problems can seem huge until you get them properly diagnosed. Thanks again for pushing me in the right direction with this. Definitely saved me from potentially making things worse by going to my old mechanic who probably wouldn't have known what to look for.