BMW 8 Series Power Windows Dead, Fix Cost Guide

Hey there! I had a similar issue with my 2020 BMW M850i last month. Initially thought it was just a window regulator problem, but turned out my battery was on its last legs. Even with relatively low voltage, these modern BMWs can show weird electrical issues, windows not working, unusual error codes, the works. Had to get my car towed to a BMW specialist. They ran diagnostics and confirmed the battery was the culprit. After replacing it, they had to reprogram the window regulators and reset various control modules. While the battery replacement itself wasn't complicated, the reprogramming was crucial to get everything working properly again. My suggestion? Get it checked by a certified BMW tech. These electrical gremlins can be tricky, and with all the sophisticated systems in newer BMWs, it's worth having someone who knows what they're doing. Better safe than sorry, especially since a failing battery can potentially damage other electrical components if left unchecked. Let us know what you find out.

Thanks for sharing your experience! That's really helpful to know about the battery being the root cause. I'll definitely get it checked by a certified BMW tech. By the way, do you remember roughly how much you ended up paying for the whole thing? Also, has everything been working fine since the fix, or have you noticed any other electrical quirks?

Hey again! Absolutely happy to update you! Since getting it fixed, my M850i has been running like a dream, no more window issues or any other electrical quirks whatsoever. The window regulator initialization problem completely disappeared after they sorted out the battery situation. The total bill came to 290 € for the battery replacement, which included the new battery itself, labor, and all the necessary reprogramming work. Honestly, while it wasn't cheap, it was worth every penny considering how smoothly everything's working now. These high-end BMWs can be a bit finicky with electrical stuff, but once you get them sorted properly, they're fantastic. I've put about 5,000 km on the clock since the repair, and I haven't had a single issue. The windows, along with all other electrical systems, are working perfectly. Just make sure you go to someone who really knows BMWs, it makes all the difference when they understand the complexity of these cars. Keep us posted on how yours turns out!

Thanks for the detailed follow-up! Just wanted to update you all on what happened with my window situation. I took your advice and went to a certified BMW technician yesterday. You were right, it was actually battery-related! The funny thing is, when I got there, the mechanic immediately suspected the battery before even hooking up the diagnostic tools. He said he sees this issue quite often with newer BMWs. The repair was pretty straightforward, but yeah, the reprogramming took a while. Ended up paying around 310 € total, slightly more than what you paid, but they also found and fixed a small wiring issue while they were at it. The windows are working perfectly now, and all those annoying error codes are gone. The new mechanic was great too, super transparent about everything and even showed me what they were doing during the repair. Really appreciate everyone's help on this. Sometimes it's just worth paying a bit more to get things done right the first time!