BMW XM Temp Sensor Chaos: Climate Controls Gone Haywire

Hey there! I had very similar issues with my 2020 BMW X7. The symptoms you're describing match exactly what I experienced last month, climate control going crazy and mirror heating failing. Turned out it was indeed the ambient temperature sensor, but there was also a loose connection in the wiring harness that connects to the climate control module. When I took it to the garage, they first tested the sensor connectivity and found the signal was intermittent. The tech showed me how the wiring had some wear near the connector, which was causing the system to get incorrect readings. They had to replace the sensor and repair the wiring harness. It wasn't a major repair in terms of complexity, but it needed proper diagnostic tools to pinpoint the exact issue. Make sure whoever works on it has experience with BMW's ISTA diagnostic system. The whole thing took about 3-4 hours to fix. Just check that they test both the sensor and the wiring, sometimes mechanics just replace the sensor without checking the connections, and then you're back with the same problem a few weeks later. Hope this helps!

Hey, thanks so much for sharing your experience! What you described sounds exactly like my issue. Really helpful to know about that wiring harness problem too, definitely gonna mention that when I take it in. Just curious, do you remember roughly how much you ended up paying for the whole fix? Also, has everything been working properly since the repair, or have you noticed any other quirks pop up?

Hey again! Great to hear back from you! Yes, I'm happy to tell you that since I got it fixed last month, everything's been working perfectly fine. The climate control is spot-on now, and the mirror heating works like a charm. No more frozen spray nozzles either! For your question about the cost, in my case, it turned out to be pretty straightforward. The mechanic found it was just a faulty cable connection to the temperature sensor, which was much simpler than needing a complete sensor replacement. The total came to 95 € including labor, which was a relief since I was initially worried it might be something much more expensive! Honestly, it was worth every penny to have it properly diagnosed and fixed. The car's running exactly as it should now, with no weird quirks or issues. The temperature readings are accurate, and all the temperature-dependent systems are working perfectly. Just make sure whoever looks at yours checks those connections thoroughly, that's often the real culprit rather than the sensor itself being bad. Let me know how it goes when you get yours sorted!

Thanks for all that info! You were spot on with your advice. Just got back from the mechanic and wanted to update you on what happened. Took it to a certified BMW specialist who actually found multiple issues. Turned out my problem was a bit more complex, had a damaged wiring harness and a failing sensor. The mechanic showed me the corroded connections, which explained all those weird temperature readings. Labor was pricier than your repair since they had to replace both parts, but honestly, I'm just glad it's fixed properly now. The whole system's working perfectly, AC's blowing cold, mirrors are heating up, and those pesky spray nozzles are finally working in cold weather. Funny thing is, they said if I'd waited longer, it could've damaged other components too. Really dodged a bullet there! Thanks again for pushing me to get it checked out properly. Definitely learned my lesson about going to qualified specialists for these specific issues.