BMW M2 Climate System Failure: AC Dead and Error Code

Hey there! I have some experience working on BMWs. Had a similar issue with my 2021 M3 last summer. The symptoms you're describing sound exactly like what I dealt with. In my case, it turned out to be a loose connection in the wiring harness that controls the ventilation system. My trusted mechanic found that one of the plugs wasn't properly seated, causing intermittent failures. The fix was pretty straightforward, they had to access the connection behind the center console, clean the contacts, and properly reseat the plug. Cost me around 95 Euro for the whole job, including diagnostic time. Car's been running perfectly since then. Before jumping to conclusions though, could you share: Does the AC fan still work at all? Are you getting any specific error messages on the display? Did this start suddenly or gradually? Might help pinpoint if you're dealing with the same issue I had.

Thanks for the detailed response! I've got around 81008 KM on the clock and just had my service last month. To answer your questions, the AC fan does work, but only on the highest setting. I'm getting error code P0401 on the display, and it started pretty suddenly during a hot day last week. The rear controls just went completely dead. I'll definitely have my mechanic check that wiring harness you mentioned. Really hoping it's just a connection issue like yours and not something more serious. Did you notice any weird sounds before your system failed completely?

Hey again! Thanks for the follow-up. Yeah, those symptoms are definitely sounding similar to what I experienced, but there's one key difference. With my M3, I didn't get the P0401 error code, and my fan worked on all settings. But before my system failed completely, I did notice this weird clicking sound coming from behind the dash when switching between temperature settings. Just thinking about it, since you mentioned it started on a hot day and your fan only works on the highest setting, it could actually be a combination of issues. My wiring harness problem was pretty straightforward, but yours might need a bit more investigation. Looking back, I wish I'd checked the fuses first before taking it to the mechanic, would've saved me some diagnostic time. Have you tried checking the fuse box yet? There's usually one specifically for the climate control system. Also, since you mentioned having a recent service, maybe worth checking if anything was disturbed during that work? Sometimes these issues can pop up right after routine maintenance if something wasn't reconnected properly. Keep us posted on what you find out. Really curious to know if it ends up being similar to my issue or something entirely different.

Thanks for all this info! I actually just checked the fuses like you suggested, all seem good, but you got me thinking about that recent service. I'll definitely bring that up with my mechanic. You're right that the timing is suspicious, especially since everything was perfect before the service. No clicking sound in my case though, which makes me think this might be a bit different from your situation. Still, I'm relieved to hear your fix was relatively simple and affordable. I've got an appointment scheduled for tomorrow morning, and I'll make sure they check that wiring harness first before diving into anything more complicated. Really appreciate you taking the time to share your experience. It's always good to have some idea of what to expect when heading to the mechanic. I'll update the forum once I get it sorted out, might help someone else down the line with similar issues!