BMW Z3 Top Issues: Flashing LED & Error Code Mystery

Hey there! I've got some experience working on BMWs. Had a pretty similar issue with my 2002 BMW Z4 last summer. The convertible top was acting up just like yours, getting stuck mid-way and showing warning lights. Took it to my trusted workshop, and it turned out to be a loose connection in the wiring harness for the top mechanism. They had to trace the cables and found a damaged plug connection. Fixed it up for about 95 Euro, and it's been working perfectly since then. Much better than having to replace the entire motor or sensors! Before I share more specific details, could you share: Have you noticed any grinding noise when operating the top? Does it happen more often when it's cold or after the car's been sitting? Did you scan for specific error codes? I know these Z series cars pretty well (also owned a Z8), so I might be able to help pinpoint the issue if you share more info.

Thanks for the detailed reply! My Z3 has 43369 KM on the clock since my last service, and I'm hearing a slight grinding noise when trying to operate the top, especially during colder weather. I haven't managed to get the specific error codes yet, but I'm planning to get it scanned tomorrow. Your wiring harness experience is really interesting, it would be great if mine turns out to be something that simple and affordable. I'll definitely get those connections checked first before jumping to more expensive repairs. I've had similar electrical gremlins with other systems in the past, so it wouldn't surprise me if that's the culprit here too.

Hey again! Thanks for the update on your Z3. After reading about the grinding noise, I'm thinking this might be a bit different from my initial wiring harness guess. When my Z4 had issues last year, it was completely silent, just stopped working. The grinding noise you're describing actually reminds me of another problem I had about two years ago. That time, it turned out the hall sensor was indeed failing, and it was causing the top to get confused about its position. I remember it cost me around 350 Euro for the sensor replacement, but it was totally worth it. The grinding noise was happening because the system wasn't properly synchronized, making the mechanism fight against itself. Given what you're saying about the cold weather making it worse, I'm leaning even more toward the hall sensor theory now. These sensors can get more finicky in cold temperatures, which matches your symptoms perfectly. When you get those error codes tomorrow, look specifically for any positioning sensor related codes, that'll help confirm it. One quick thing you can try before taking it in: clean around the sensor area carefully. Sometimes dirt buildup can cause similar symptoms. Didn't work in my case, but worth a shot before spending money on repairs. Let me know what those error codes say when you get them. We can compare them with what I got when my sensor went bad.

Thanks for all that additional info! After hearing about your experience with the hall sensor and the similar grinding noise, I'm feeling more convinced that's probably what I'm dealing with too. The cold weather connection you mentioned makes a lot of sense, it definitely acts up more when temperatures drop. I'll definitely get those error codes tomorrow and clean around the sensor area like you suggested. Even if it's just to rule things out, it's worth trying before spending money on repairs. I'm actually a bit relieved to hear that when you got your hall sensor replaced, it solved the problem completely. At least I know if that turns out to be my issue, there's a clear fix, even if it costs around 350. When I get the codes tomorrow, I'll update this thread with what I find out. Really appreciate you taking the time to share your experiences, it's helping me feel more prepared for my mechanic visit. Thanks for walking me through this!