BMW Climate Controls & Sensors Failing Mysteriously

Hey there! Had the same nightmare with my 2009 BMW 5 diesel (similar issue at 180k km). Initially thought it was the fog sensor too, but turned out to be a faulty wiring harness connection to the climate control module. Found this out last month at the garage when my car showed identical symptoms. The washer nozzles and mirror heaters failing together with the AC issues is a classic sign of a disconnected or corroded main cable bundle. The technician traced it to a connector behind the glovebox that had gotten loose and corroded over time. It wasn't a major repair in terms of parts, but accessing the area was tricky and required partial dashboard removal. Just make sure they check the wiring connections before replacing any sensors. These symptoms typically point to an electrical connection issue rather than sensor failure in BMWs from that era. Hope this helps! Best regards

Hey, thanks for sharing that info! Really appreciate the detailed explanation about the wiring harness, sounds exactly like what I'm dealing with. I'm curious, do you remember roughly how much you ended up paying for the repair? Also, has everything been working smoothly since they fixed it, or have you noticed any other quirks pop up? Would love to know what to expect if I need the same fix. Cheers!

Hey again! Glad I could help earlier! Since my last post, I can confirm the fog sensor issue got completely sorted out. The mechanic was spot on with the diagnosis, it was indeed that pesky cable connection we discussed. Total bill came to 95 € to fix the faulty connection, which honestly wasn't as bad as I feared. The best part? Everything's been working like a charm since the repair. Climate control's back to normal, washer nozzles are spraying perfectly, and those mirror heaters kick in just fine in cold weather. No more foggy windows either! It's such a relief when these electrical gremlins turn out to be something relatively straightforward. If your symptoms match what I had, you're probably looking at a similar repair cost. The trickiest part was getting to that connection behind the glovebox, but once they sorted that out, it was smooth sailing. Haven't had a single problem with any of those systems in the past month. Let me know how you get on with yours! Cheers!

Thanks for the follow-up! Just got back from the mechanic yesterday, and you won't believe it, my story turned out quite different! Took your advice about checking the wiring first, but turns out my issue was actually a blown fuse and a clogged drain tube. The mechanic found it pretty quickly, but getting to it was a pain. Cost me about 150 bucks total, including cleaning out all the gunk that had built up. Funny thing is, while they were poking around, they spotted a small crack in my coolant reservoir that could've caused bigger problems down the line. Got that sorted too while I was there. Car's running like new now, no more foggy windows, AC's blasting cold air, and everything's working as it should. Really glad I asked here before letting them replace the whole fog sensor unit like the last mechanic suggested. Would've wasted a bunch of money for nothing! Thanks again for pointing me in the right direction, even though my fix ended up being different. Take care!