BMW 8 Series Windshield & Rear Heating Failure Help

Hi there! I have some experience with car repairs, and I actually faced a similar issue with my 2021 BMW 6 Series last winter. Initially thought it was just the heating system, but turned out the battery was heavily discharged, which affected multiple electrical systems including the windshield and rear window heating. Took it to my regular workshop, and they ran a full diagnostic. The battery wasn't holding charge properly and needed replacement. Total repair cost was around 290 Euro, which included the new battery and labor. Since then, all heating systems have worked perfectly. What's your car's mileage and have you noticed any other electrical issues? Might help pinpoint if you're dealing with the same problem. Like, does your start-stop system work normally? Or have you seen any dimming in the dashboard lights? Let me know these details and I might be able to help more!

Thanks for sharing your experience! My car has 50166 KM and had its last service just 2 months ago. Actually, now that you mention it, I have noticed the start-stop system acting a bit weird lately, sometimes hesitating before restarting. The dashboard lights seem normal though. The battery thing makes sense, I'll definitely get that checked out. Did you notice any warning signs before your battery completely gave out? Really appreciate the tip about checking the electrical system as a whole rather than just focusing on the heating issue!

Hey again! Yes, absolutely, thinking back to my experience, I did notice some warning signs with my BMW before the battery completely failed. The start-stop hesitation you're describing sounds really familiar, that's exactly how mine started acting about two weeks before the heating systems gave up completely. In my case, I also noticed the central locking would sometimes take an extra second to respond, and occasionally the infotainment system would reboot out of nowhere. These were such subtle changes that I didn't connect the dots at first, but they were definitely early warning signs of the battery issue. With your car being a 2023 model and only having around 50K on the clock, I wouldn't normally expect battery issues this early. But sometimes factors like frequent short trips or extreme temperatures can affect battery life. Since you're experiencing similar symptoms to what I had, I'd definitely recommend getting the battery checked ASAP. One quick test you can try: next time you start the car, pay attention to how bright your headlights are at idle versus when you rev the engine slightly. If there's a noticeable difference in brightness, that's another sign pointing to a potential battery/charging system issue. Let me know what you find out, I'm curious if it turns out to be the same problem I had!

Thanks so much for all the detailed advice! I just tried the headlight test you suggested, and there's definitely a slight difference in brightness when revving, not super obvious, but noticeable. That's really concerning. I've actually scheduled an appointment with my workshop for tomorrow morning. You're right about the short trips, I've been doing loads of those lately, which probably hasn't helped the battery situation. Funny how all these little signs were there, the start-stop hesitation, and now that you mention it, I've noticed my central locking has been a bit sluggish too. I just didn't connect these issues until you pointed them out. I guess I was too focused on just the heating problem to see the bigger picture. I'll make sure to have them check the entire electrical system and the battery. Really hope it's just a battery issue like yours was and nothing more complicated. Thanks again for helping me figure this out, you've probably saved me both time and money by pointing me in the right direction. I'll update you once I get it checked out!