BMW 7 Climate Control System Complete Failure, Help!

Hi there! I've had some experience working on cars, and this sounds really similar to what I faced with my 2002 BMW 5 Series diesel last winter. I first noticed these exact symptoms, dead temp display, AC issues, and frozen nozzles. Took it to my regular workshop, and turns out it was a faulty wiring connection to the temperature sensor. The mechanic found corroded cables and a loose plug. The repair was pretty straightforward, they replaced the wiring harness and connector, cost me about 95 Euro. Could you share which engine variant you have in your 7 Series? Also, are you getting any specific error codes? This would help me give you more targeted advice, as these BMW models share quite a few common components. BTW, if you're getting similar symptoms, it's worth checking this soon, driving without proper temperature readings can lead to bigger issues down the line.

Thanks for sharing your experience! I've got the M67D44 diesel engine, and just hit 148153 KM on the clock. Was a bit worried after my last service that these issues might pop up. Those symptoms you described match mine exactly. Good to know it might just be the wiring, was dreading it might be something more serious with the electronics. The error codes I'm getting are mainly related to the temp sensor circuit, but I'll need to double-check the exact codes. Did your mechanic mention how long the repair took? Hoping to get this sorted before the weather gets worse. It's a pain not having working mirror heaters and washer nozzles.

Hey again! Thanks for the follow-up about your M67D44. Yeah, my repair job took around 2-3 hours total, and honestly, it's been working perfectly since then. The mechanic actually showed me the corroded wiring, it was pretty nasty! With your mileage being similar to what mine was when I had the issue, it's not surprising you're seeing these symptoms. These BMWs tend to develop these wiring problems around the 140-150K mark, especially in the temp sensor circuit. One thing I forgot to mention in my first reply, after they fixed mine, they recommended checking the connections every year during service. I've been doing that, and it's helped prevent any repeat issues. Also, they applied some special waterproof sealant to the new connections, which has kept everything dry and corrosion-free. The mirror heaters and washer nozzles started working right away after the fix. Such a relief, especially since I was also worried about more serious electronic issues at first. If your error codes are similar to what I had, you're probably looking at the same repair. It's definitely worth getting it sorted soon, it's a relatively simple fix that prevents bigger headaches later. Let me know how it goes after you get it checked out. Would be interested to hear if it's the same issue!

Thanks so much for all this detailed info! Really relieved to hear it's likely just a wiring issue. Just booked my car in for next week, and shared those details about the M67D44 and error codes with the workshop. They seemed pretty confident it's the same problem you had. Great tip about the annual connection check and waterproof sealant, I'll definitely ask them about that. The 2-3 hour repair time sounds reasonable too. Keeping my fingers crossed it's as straightforward as your fix was. I'll update you once it's done. Really appreciate you taking the time to share your experience, it's helped put my mind at ease about what could have been a much bigger headache!