BMW M4 Climate Control Dead, Temp Sensor Issue?

Hey there! I had a somewhat similar issue with my 2017 BMW M3 last summer (I have some experience working on cars, mostly basic maintenance stuff). The symptoms were exactly like yours, climate control went completely dead, and the display was showing errors. After taking it to my trusted workshop, they found that the wiring harness connecting to the climate control module had some damaged pins and loose connections. Total repair cost was 95 Euro, which covered the diagnostic work and fixing the connections. Before jumping to conclusions about the temp sensor, could you share: Are you getting any specific error codes? Does this happen all the time or intermittently? Did you notice any other electrical issues? I know how annoying climate control problems can be, especially since the M4 shares a lot of components with the M3. Would love to help you narrow this down further.

Thanks for sharing your experience! My M4 is actually showing the error code "FL-209" intermittently, and it's definitely happening more frequently now than when it first started. I haven't noticed any other electrical issues, and everything else works perfectly fine. The car has 44561 KM on it and was just serviced last month, so I'm a bit frustrated this is happening. Your wiring harness situation is interesting, I'm wondering if I might be dealing with something similar since my issues started showing up on particularly bumpy roads. Might be worth checking those connections first before diving into more expensive repairs. Did your mechanic mention if this is a common issue with these models?

Hey again! Yes, that error code FL-209 rings a bell, it's exactly what I saw in my M3 before getting it fixed. When you mentioned it happens more on bumpy roads, that's pretty much identical to what I experienced. My issues started showing up out of nowhere, but I definitely noticed it acting up more when hitting rough patches. Just to give you a bit more detail about my repair, my mechanic actually showed me the harness after he took it out. There were a couple of pins that had worked themselves loose over time, and one of the connectors had some slight corrosion. He mentioned it's not super common, but he's seen it a few times on the F8x platform (that's what our M3/M4s are based on). Quick tip from my experience, before you take it in, try gently pushing on the climate control panel while it's acting up. If the error temporarily goes away or the system responds differently, it's almost certainly a connection issue like what I had. That's actually how I figured out it might be wiring-related in my case. If your mileage is only 44561 KM, this should definitely be covered under warranty. Mine wasn't covered anymore since I was out of warranty, but that 95 euro repair was way better than the 700+ they initially quoted me for replacing the entire temp sensor module. Let me know how it goes, really curious if it turns out to be the same issue!

Thanks so much for all the detailed info! I just tried your tip about pushing on the climate control panel, and sure enough, the system actually responded for a moment! That's a huge relief, pretty sure we're looking at the same issue now. I'll definitely get it checked out this week and ask them specifically about the wiring harness. Really glad you mentioned the warranty coverage too, I completely forgot my car should still be under warranty since it's relatively new. That'll save me some cash! Thanks again for sharing your experience. It's super helpful to know exactly what to look for and what to tell the mechanic. I'll update this thread once I get it sorted out in case anyone else runs into the same problem in the future. Really appreciate everyone's help here!