Z3 Power Windows Dead: Fixing Regulator Fault

Hey there! I had a similar issue with my 2004 BMW Z4 last year. When my windows stopped working, it turned out the problem was actually related to a weak battery, not the regulators themselves. The battery was causing electrical system fluctuations, which prevented proper window initialization. After replacing the old battery with a new one and doing a basic window reset (holding the switch up for several seconds), everything worked perfectly again. It wasn't a serious repair at all, just basic maintenance that was overdue. If that doesn't solve it, then yes, it could be the window regulators. But I'd definitely check the battery first since it's a simpler fix. Make sure whoever checks it uses proper diagnostic tools to verify the actual issue before replacing parts. Just my experience, hope it helps with your Z3!

Hey, thanks for sharing your experience! The battery solution sounds way better than having to deal with regulators. Would you mind telling me roughly how much you ended up paying for the new battery and installation? Also curious if you've had any other electrical quirks pop up since then? My Z3's getting up there in age, so I'm trying to stay ahead of potential issues.

Hey again! Glad I could help! Yeah, I went to the mechanic last week and they confirmed it was indeed the battery causing the window issues. Got that sorted out and the window initialization problem completely disappeared, such a relief! The whole thing, including the new battery and labor, came to 290€. Honestly, it was worth every penny since it fixed the problem right away and saved me from potentially more expensive repairs down the line. Since getting the new battery, all the electrical systems have been running smoothly, no more quirks! My Z4's about the same age as your Z3, and I've learned that keeping the battery in good shape really helps prevent those unusual electrical gremlins from popping up. These older BMWs can be sensitive to voltage issues, but once you get the battery situation sorted, they're pretty reliable. Just make sure whoever does the work uses a proper battery tender during the swap to preserve all the car's electronic settings. Definitely learned that lesson the hard way with previous repairs!

Thanks for all the great info! Just got back from the mechanic today and you were absolutely right, it was the battery! They did the diagnostic test and showed me how the old battery was barely holding a charge. Got it replaced for about the same price you mentioned, and they used that battery tender thing you talked about. All the windows are working perfectly now, and the error code is gone. What a relief! It's so much better than my last mechanic experience where they tried to convince me I needed a complete window system overhaul. Really glad I asked for advice here first. The funny part was when the mechanic was showing me the old battery, it looked fine on the outside but was definitely toast on the inside. Going to keep a closer eye on the battery's age from now on. The car's running great now, and all the electrical stuff is back to normal. Thanks again for steering me in the right direction!