BMW X3 Heat System Failure, Water Valve Warning Signs

I had a similar issue with my 2018 BMW X5 last winter. The symptoms were exactly what you're describing, inconsistent heating and zone problems. Initially thought it was the water valve too, but when I took it to the garage, it turned out to be a faulty wiring connection to the climate control module. The technician found corroded pins in the main connector plug that controls the heating system. This was causing intermittent communication issues between the control module and the heating components. It wasn't a major repair, but it definitely needed professional attention since it involved dealing with the electrical system. They had to clean the connectors and replace some wiring. The repair solved both the uneven heating and the error code issues. If you're getting error codes, have them specifically check the electrical connections first before replacing any major components. It's worth finding a BMW specialist for this kind of electrical issue.

Thanks for sharing your experience! That's super helpful, and it's good to know it might not be the water valve after all. The electrical connection issue actually makes a lot of sense with what I'm experiencing. Just curious, do you remember roughly how much you ended up paying for the repair? Also, has everything been working properly since they fixed it, or have you noticed any other heating quirks?

Hey there again! Glad I could help with my previous response. So after I saw your question, I wanted to update you, I actually had both issues: the corroded electrical connections AND a faulty water valve. The mechanic found and fixed both problems. They charged me 95 € for sorting out the cable and connection problems. Pretty reasonable, considering all the diagnostic work they had to do. And you asked about how it's been working since, I'm happy to report it's been running like a charm! The heating system is now working perfectly in all zones, no more cold spots or weird temperature fluctuations. The error codes haven't come back either. It's been about a year now, and even through the cold season, everything stayed consistent. Looking back, I'm really glad I got both issues fixed properly rather than just assuming it was one or the other. These BMWs can be tricky sometimes, but once you get them sorted, they're solid. Hope this extra info helps with your decision!

Just wanted to update everyone on what happened with my BMW heating issue. After getting all your advice, I bit the bullet and took it to a different mechanic, a certified BMW specialist this time. Man, am I glad I did! They found exactly what mentioned, corroded electrical connections were the main culprit. The diagnostic process was super thorough. Turned out I had a small coolant leak near the control module that was causing the corrosion. Total bill came to about 180 for everything, including the diagnostic work and fixing both the leak and electrical issues. Way less than I expected honestly! Got my car back yesterday and the difference is like night and day. Heat's working perfectly in all zones now, and that annoying error code is gone. Thanks everyone for steering me in the right direction, saved me from potentially getting unnecessary expensive repairs at my old mechanic. Really appreciate the help!