BMW X7 AC System Dead, Heat Sensor Troubleshooting

Hey there! I have some experience working on BMWs, as I own a 2018 BMW X5 (and previously had an X3). I actually faced a very similar AC issue last summer. The symptoms were exactly like yours, complete AC failure and dashboard warnings. Initially thought it was the sensor too, but it turned out the AC control unit itself was defective. Had to get it replaced at my local workshop, wasn't a fun bill at 980 Euro, but it fixed the problem completely. Before you head to the shop though, could you share: Any specific error codes you're getting? Did it fail suddenly or gradually get worse? Do you hear any weird noises when trying to use the AC? This info would help narrow down if you're dealing with the same issue I had. These luxury German cars can be tricky with electronics, but they're usually quite fixable once you identify the exact problem.

Thanks for sharing your experience! My X7 just hit 16895 KM and had its latest service a few months back. The AC actually died suddenly while driving, no warning signs before that. Getting error code P0531 in the dash, and there's a slight clicking sound when I try to turn on the climate control. I was hoping it'd be just a sensor, but after reading your response, I'm worried it might be the control unit too. Really not looking forward to that repair bill! Did you try any temporary fixes before replacing the unit, or was replacement the only solution that worked?

Hey again! Yeah, that P0531 code and the clicking sound are exactly what I experienced with my X5. When you mentioned the clicking, it immediately reminded me of my situation. I actually tried a few temporary fixes before biting the bullet on the control unit replacement. First, I disconnected the battery for about 30 minutes hoping to reset the system, that worked for like... maybe 2 days before the problem came back. Then I tried cleaning the electrical connections to the control unit, which did absolutely nothing. With your mileage being so low (mine was around 38000 KM when it happened), you might want to check if you're still under warranty. I wasn't so lucky with mine, hence the painful repair bill. Here's the thing though, while my issue ended up being the control unit, when the clicking sound is involved, there's a small chance it could also be the actuator motors behind your dash. They're cheaper to replace than the whole control unit. But given all your symptoms match mine so perfectly (especially that P0531 code), I'd put my money on the control unit being the culprit. One word of advice: if you do need the control unit replaced, make sure they reprogram it properly. Mine needed some coding after installation to work with the car's systems. Learned that the hard way when the first installation didn't go quite right! Let me know what you end up finding out. Always curious to hear if these issues follow the same patterns.

Thanks so much for all this detailed info! After hearing your experience, it definitely sounds like I'm dealing with the same control unit issue. The clicking sound and error code match exactly. I'll check my warranty status right away, you got me hopeful since my X7 is still pretty new. I think I'll skip trying the temporary fixes you mentioned since they didn't work long-term for you. No point wasting time when it's likely going to need replacement anyway. Really appreciate the tip about making sure they properly program the new unit, will definitely bring that up with the workshop. I'll probably book it in next week and brace myself for that repair bill if it's not covered by warranty. Thanks again for sharing your experience, it's saved me from going down the wrong path with sensor replacements. Will update the thread once I get it fixed!