BMW M2 AC Problems, AUC Sensor & Blower Issues

Hey there! I've got some experience with cars, and I actually faced something really similar with my 2014 BMW M3. The symptoms were almost identical, nasty smells and blower issues. After struggling with it for a few days, I took it to my regular workshop. Turned out it was just a faulty cable connection to the AUC sensor. The fix wasn't too complicated, they replaced the connection and cleaned up the area. Cost me about 95 Euro total, but totally worth it as it's been working perfectly since then. Before I share more details about my experience, could you tell me if you've noticed any other symptoms? Also, have you checked if the issue happens more during specific weather conditions? This info would help me understand if you're dealing with exactly what I had. If you've got a trusted BMW mechanic, I'd definitely recommend having them take a look, as these sensors can be a bit tricky to diagnose correctly.

Thanks for sharing your experience! My M2 has 31716 KM on the clock, and I just had my regular service last month. Actually, now that you mention weather conditions, I've noticed the smell gets worse on humid days. Haven't spotted any other issues besides what I mentioned, but it's really annoying when stuck in traffic. Good to hear your fix was relatively straightforward and not too expensive. I'll definitely get it checked out by my mechanic then, better safe than sorry, especially since it worked out well in your case. Did your mechanic mention anything about preventive measures to avoid this issue in the future?

Hey again! Glad I could help earlier. Yeah, the humidity connection makes total sense, that's exactly what I experienced with my M3 too. Actually, after my mechanic fixed the cable connection, he shared some useful tips to prevent future issues. He mentioned that these AUC sensor problems often pop up because of debris and moisture buildup around the connection area. So now I make sure to keep the area around the sensor clean and dry. Also, he recommended running the AC system for at least 10 minutes once a week, even in cooler weather, to keep everything working smoothly. Since my repair, I've put another 20,000 km on my M3 without any similar issues. One thing I've started doing is occasionally checking the air quality when I start the car, if you notice any delay in the auto-recirculation response, that might be an early warning sign. Just a heads up, while my fix was pretty straightforward, sometimes these issues can be connected to other AC components. My mechanic mentioned that in some cases, it could be linked to the blower motor control module. But given your symptoms sound identical to what I had, I'm pretty confident you're dealing with the same connection issue. Let me know how it goes after your mechanic checks it out!

Thanks so much for all that detailed info! It's really helpful to know about the maintenance tips, I had no idea about running the AC weekly or checking the auto-recirculation response. Makes total sense about the humidity and debris being potential culprits. I've booked an appointment with my mechanic for next week, and I'll definitely mention your experience with the cable connection issue. Really hoping it'll be a simple fix like yours was! Thanks again for taking the time to share all this, it's given me a much better idea of what to expect. I'll keep an eye on those early warning signs you mentioned too. I was worried it might be something major, but you've put my mind at ease a bit. Will update you after the mechanic takes a look!