BMW Z3 AC Dead with Climate Control Panel Issues

I had almost identical issues with my '05 BMW Z4 last summer. The AC control panel died completely, no lights, no response. Got the same error messages on the dash display too. Took it to the garage and turned out the AC control unit itself was faulty. The main circuit board inside had failed. They had to replace the entire control module, not just a sensor. It was a serious repair since they needed to remove parts of the dashboard to access and replace the unit. The symptoms are very similar to what you're describing, complete AC failure and dashboard errors usually point to the control unit rather than just a sensor issue. The repair resolved all the problems and the AC has worked perfectly since then. My suggestion would be to get it properly diagnosed at a reputable shop that specializes in German cars. This isn't really a DIY fix given the electronics involved and dashboard disassembly required.

Thanks a lot for sharing your experience, that's super helpful! I was wondering how much you ended up paying for the control unit replacement? And has everything been running smoothly since the repair, or have you noticed any other quirks popping up? I'd really appreciate knowing what to expect cost-wise before I head to a shop.

Hey there again! Just wanted to follow up about the costs, I ended up paying 980 € for the AC control unit replacement. Actually, turns out I had both issues, they found that temperature sensor in the heat exchanger was also faulty and fixed that while they were in there. The good news is everything's been running perfectly fine since the repair, no quirks, no issues, just smooth operation. The AC blows nice and cold now, all the controls work as they should, and those pesky dashboard error messages are gone for good. I know it wasn't cheap, but honestly, it was worth every penny to have it working properly again, especially during those hot days. My advice would be to just bite the bullet and get it done, these kinds of electrical issues usually don't fix themselves and can sometimes get worse if left unchecked. The repair took about a day at the shop, and they had to order the parts in advance, so you might want to factor that into your planning. Let me know if you need any other details about the repair process!

Thanks so much for all the detailed info! I actually just got back from a certified BMW shop today. You were spot on, it was the control unit that needed replacing. Cost me about the same as yours, and they also caught a worn-out sensor while they were at it. The whole experience was way better than my last mechanic. These guys actually showed me the faulty parts and explained everything. No sketchy business this time! They had it done in a day, just like you said. Driving back home was like having a completely different car, AC is ice cold now, no more warning lights, and everything's working perfectly. Guess sometimes you really do need to spend the money to get things fixed right. Really glad I asked here first, saved me from going back to that questionable mechanic and probably getting a botched repair job. Time to enjoy my properly functioning AC! Thanks again for helping me avoid a potential headache with this repair.