BMW XM Electrical Nightmare: Battery & Power Issues

Hey there! I have some experience working on BMWs. I went through something very similar with my 2020 BMW X6 last year. Had almost identical symptoms, battery issues, power drops, warning lights, the works. Turned out it was indeed a faulty generator. I took it to my regular workshop where I've been going for years. They diagnosed it pretty quickly and had to replace the whole generator unit. Cost me about 960 Euro total, but it solved all the electrical problems completely. Your symptoms sound exactly like what I experienced. Before replacing anything though, any chance you could share: Current mileage? When did these issues start? Have you noticed any unusual sounds from the engine bay? With the M Series being a bit different from my X6, having these details would help me give you more specific advice about what to look out for. The generator issue is pretty common across the brand though, had a with a X5 who dealt with the same thing.

Thanks for the detailed response! My XM has 14614 KM and just had its recent service. The issues actually started about 2 weeks ago, first with flickering dash lights, then it got progressively worse. I haven't noticed any unusual sounds from the engine bay, but the battery warning light keeps coming on during drives. Your experience with the generator replacement is really helpful to know. I was worried it might be something more serious. Good to hear replacing the generator fixed all those similar symptoms. Think I'll get it checked out at the dealer since it should still be under warranty. I'd rather not risk any DIY fixes on such a new car.

Hey again! Glad my previous response was helpful. When I read about your mileage and warranty status, I definitely recommend going straight to the dealer. My X6 was out of warranty when I had the generator issue, which is why I went to my regular workshop. Since you mentioned it started with flickering lights, that's exactly how mine began too. Within about 2-3 weeks, I was dealing with all those other symptoms, just like you're experiencing now. The fact that your battery warning light comes on during drives is also identical to what I went through. The good news is that since your XM is still under warranty, you won't have to deal with the costs I faced. Just make sure to document when these issues started and what symptoms you've noticed, it'll help speed up the warranty process. One thing though, don't wait too long to get it checked. In my case, I drove around with the issues for about a week before getting it fixed, and it ended up completely draining my battery. Had to get a jump start just to get it to the workshop. Not fun at all! Let me know how it goes at the dealer. I'm really curious if it turns out to be the same generator issue as mine.

Thanks so much for the heads up about not waiting too long! I've actually already called the dealer and booked it in for tomorrow morning. Really don't want to risk getting stranded somewhere with a dead battery like you did. Your advice about documenting everything is super helpful too, I've already made notes of all the symptoms and dates on my phone to show them. It's actually quite reassuring to hear that your experience was so similar. I was honestly starting to worry that I'd somehow messed up my brand new car! I'll definitely update you once the dealer checks it out. Really hoping it's just the generator and nothing more complicated. Thanks again for all your help, it's made me feel a lot more confident about dealing with this whole situation!