BMW 5 Series Power Seat Mystery, Troubleshooting Guide

Hey there! I've got some experience with BMWs, having owned a 1999 BMW 3 Series and currently driving a 7 Series. I'd say I have low experience with car repairs, but I actually faced a similar electrical issue recently. My power seats were acting weird just like yours, along with some other electrical glitches. After taking it to my trusted workshop, they diagnosed a heavily discharged battery that was basically on its last legs. The whole repair, including a new battery and system check, cost me 290 Euro. The symptoms you're describing sound very familiar. The car's electronics get really wonky when the battery's dying because the system can't get enough juice to power everything properly. Before I can share more specific advice, could you share: Have you noticed any other electrical issues? Does your car take longer to start than usual? When was the last time you replaced the battery?

Thanks for sharing your experience! Mine also had those electrical gremlins with the seats, but my issue turned out to be different. Got it checked at my last service (172343 KM) and it was actually a faulty seat control module, not the battery. The module was showing corrosion damage. Tested the battery and it was fine, but that control unit was toast. I went ahead and replaced the module plus cleaned up all the connections. Been working perfectly since then, no more profile glitches or adjustment problems. Total repair was about 400 though, those BMW electronic parts don't come cheap! Just wanted to share since it might save someone else some troubleshooting time. Let me know if you need more details about the repair.

Thanks for the follow-up! Yeah, I feel a bit silly now about my battery suggestion. My 3 Series had similar symptoms but yours was definitely more specific to the seat control module. These BMWs can be tricky with electrical issues, sometimes what looks like a battery problem is actually something more complex. I actually learned something from your case. Had no idea the seat control modules could corrode like that. Makes sense though, considering all the electronics packed into these cars. And you're absolutely right about those BMW parts prices, they really know how to hit the wallet! 400 sounds pretty reasonable for that repair though. I remember when I had to replace some electronics in my old 3 Series, it cost way more than that. Did they mention how the corrosion happened in the first place? Might be worth keeping an eye on in the future. Real glad you got it sorted out. Nothing worse than those intermittent electrical gremlins in these cars. Your solution might help other BMW owners facing the same issue. These seat modules seem to be a common failure point in the older models.

Thanks for the detailed explanation about the seat module issue! Actually, when I asked my mechanic about the corrosion, they mentioned it's fairly common in these older BMW models. Apparently, the module's location makes it susceptible to moisture buildup over time, especially since mine's a 2001 model. I'm keeping a close eye on the other electronic systems now, just to be safe. Already started documenting any weird behavior in case something else acts up. The mechanic suggested regular electronic system checks during services, which makes sense given the car's age. You're right that 400 wasn't too bad considering BMW parts pricing. I was actually bracing for much worse when they first mentioned the control module! At least now I know what to look for if it happens again. These cars are amazing when everything works, but man, they sure keep us on our toes with these electronic quirks.