BMW X4 Temperature Sensor Chaos, Multiple Systems Failing

Hey there! I had a similar issue with my 2018 BMW X3 last winter (I have some experience working on cars as a hobby). The symptoms were almost identical, temperature display wasn't working, climate control went crazy, and the whole HVAC system was acting up. Turned out it was a faulty wiring connection to the ambient temperature sensor. My trusted mechanic found corroded pins in the connector plug, which was causing all these issues. Total repair cost was 95 Euro, mostly labor for diagnosing and fixing the connection. For a proper diagnosis, could you tell us: Have you noticed any error messages on the dashboard? Did these issues start suddenly or gradually? Are you experiencing this only when the car is cold or all the time? If it's the same problem, it's usually a straightforward fix, but knowing these details would help confirm if we're dealing with the same issue.

Thanks for sharing your experience! I've got the same car but with just 17337 KM on the clock from my latest service. These issues started suddenly about a week ago, no warning lights or error messages on the dash though. It happens all the time, regardless of whether the engine's cold or warm. Hearing that it could be just a corroded connection is actually a relief. Was worried it might be something more serious. Gonna have my mechanic check those sensor connections first thing. Really appreciate the tip about the connector pins, gives me something specific to point them towards.

Hey again! Following up on your response, yeah, those symptoms definitely sound similar to what I experienced. What's interesting is that my X3 also had no warning lights when this happened, which initially made it more confusing to diagnose. Since your mileage is pretty low at 17337 KM, I'd bet even more on it being a connection issue rather than a sensor failure. In my case, moisture had gotten into the connector housing and caused the corrosion. The fact that it started suddenly also matches my experience, I remember driving one day and everything was fine, then the next morning, boom, all those systems went haywire. Quick tip from my experience, when your mechanic checks it, make sure they also inspect the wiring harness near the sensor for any signs of wear or damage. In my car, we found that part of the protective sleeve had worn slightly, which probably contributed to the moisture getting in. The repair was really quick once they identified the issue, took about an hour total. Just keep in mind that they might need to clear the error codes from the system after fixing the connection, even if you're not seeing any warning lights. The car's computer sometimes needs a proper reset to get everything working normally again. Let me know how it goes, curious to see if it's the same issue!

Thanks so much for the detailed follow-up! You've seriously put my mind at ease. I've already called my mechanic and booked it in for tomorrow morning. Mentioned everything about the connector, wiring harness, and possible moisture damage, they seemed to know exactly what I was talking about. Really glad I asked here before taking it in. At least now I won't feel completely clueless when they start explaining things. And good call about the system reset, I'll make sure to mention that too, even though there aren't any warning lights. I'll definitely update this thread once it's fixed. Hopefully it'll help someone else with similar issues down the line. Thanks again for taking the time to share your experience, it's been super helpful!