BMW X5 Cabin Odor & Climate Control Problems Solved

Hi there! I had a similar issue with my 2003 BMW X3 last year (I also own a 330i). I have some experience working on cars, but mostly basic maintenance stuff. The symptoms were exactly like yours, nasty smell in the cabin and climate control acting up. Took it to my trusted mechanic who found it was indeed a bad cable connection to the AUC sensor. The connector had corroded over time. Total repair cost was 95 Euro including labor and parts. Could you share more details about your X5, like mileage and whether you've had any previous AC system repairs? This would help determine if you're dealing with the same issue I had. Basic thing you can check first: Make sure there's no obvious damage to the wiring you can see near the sensor. But given the symptoms, it's best to have a pro look at it.

Thanks for the detailed response! My X5 has 122821 KM on the clock and just had its service last month. The AC was working perfectly until about two weeks ago when these issues started. Haven't had any previous AC repairs on this car. Checked the visible wiring but couldn't spot anything obvious. Good to know about your experience with the corroded connector, that price sounds reasonable if it's the same issue. Will probably take it to a shop next week to get it diagnosed properly. Are you still having any issues after your repair?

Hey again! Just wanted to follow up on your question. After my repair last year, everything has been working perfectly fine on my X3, no more bad smells or climate control issues. The corroded connector was definitely the culprit in my case. Since your X5 just started showing these symptoms suddenly and you've had regular maintenance, it does sound very similar to what I experienced. Mine also worked fine until it didn't, these things tend to fail without warning. And with similar mileage too (mine had about 130K when it happened). One thing I forgot to mention in my previous reply, when my mechanic fixed it, he also applied some dielectric grease to the new connector to prevent future corrosion. Might be worth asking your shop to do the same when they repair yours. It's a small detail but could save you from having the same problem again down the road. Let me know how it goes when you get it checked out. Always good to share experiences with these common BMW quirks!

Thanks so much for the additional info and tips! Really appreciate you mentioning the dielectric grease, that's exactly the kind of practical advice I was hoping for. I'll definitely ask the mechanic about applying it when I take the car in. It's reassuring to hear your repair has held up well, especially since our cars had such similar symptoms and mileage. I've already called a local BMW specialist and booked it in for next Tuesday. Given what you've shared about your experience, I'm feeling much more confident about the potential diagnosis and repair costs. Will probably be worth every penny to get rid of that awful smell! Thanks again for taking the time to share your experience, really helped put my mind at ease about this whole situation.