BMW 7-Series Electrical Gremlins: Multiple System Failures

Hey there! I had a somewhat similar issue with my 2002 BMW 5 series. I've got some experience working on cars, mostly basic maintenance and electrical stuff. That purple xenon and electrical gremlins combo sounds familiar. My 5 series was doing strange things with the dashboard and lights. Turned out to be a bad connection in the main wiring harness near the steering column. My trusted mechanic found corroded pins in one of the main connectors that was causing all sorts of weird electrical behavior. Fixed it for about 95 Euro, they had to clean and reseat several connections, plus replace a damaged plug. Everything's been working perfectly since then. Before I can offer more specific advice, what's the exact model of your 7 series (740i, 750i)? Also, when did these issues start showing up? Did they all appear at once or gradually?

Thanks for the response! I've got a 740i with 38854 KM on the clock. Just had the latest service done too. Mine started quite suddenly, all symptoms appeared within the same week. Actually, it happened right after we had some heavy rain. I'm starting to think it might be water-related corrosion like you mentioned, rather than just a faulty turn signal. Did your issues also show up suddenly? Really appreciate the heads up about checking the wiring harness, I'll mention this to my mechanic next time.

Hey again! Yeah, after reading about the rain and sudden onset of problems in your 740i, I'm even more convinced it's similar to what I dealt with on my 5 series. Mine also started acting up pretty suddenly, literally after a really wet weekend. The timing of your issues showing up right after heavy rain really rings a bell. These old BMWs can be prone to water getting into places it shouldn't, especially around the wiring harness area. In my case, water had actually seeped in through a slightly degraded seal near the firewall, which then ran down into that connector I mentioned. Given your car's relatively low mileage, the seals might still look good but could have hardened with age. I'd definitely get your mechanic to check the weatherstripping and seals around the firewall area, plus those main connector points. Mine looked fine at first glance, but when we really got in there, you could see the corrosion buildup. The sudden appearance of multiple electrical issues is almost always related to wiring rather than individual components. Since you've just had a service done, maybe ask them if they noticed any water residue or corrosion while they were working on it. Keep us posted on what you find, always curious to hear how these things turn out!

Thanks so much for the detailed follow-up! You've really given me something solid to work with here. Makes total sense about the water seepage, I actually noticed some dampness in the trunk last month but didn't think much of it at the time. That could definitely be related. I've just called my mechanic and mentioned the wiring harness and connector points you talked about. He seemed quite interested and agreed it's worth checking out, especially given the timing with the rain. Said he'll do a thorough inspection of the seals and weatherstripping too. Got an appointment scheduled for next week. Will definitely be cheaper and make more sense to check these connections first before replacing any individual components. I was worried this would turn into some crazy expensive repair, but your experience gives me hope it might be something relatively straightforward. Really appreciate you taking the time to share your experience, it's exactly the kind of real-world insight I was hoping for. I'll update the thread once I get it sorted out in case anyone else runs into similar issues with their 7 series.