BMW 7 Series Heating System Failures: Water Valve Issues

Hey there! I have some experience working on BMWs. Had a similar issue with my 2013 BMW 5 Series Diesel (and previously owned a 3 Series too). The symptoms you're describing sound exactly like what I dealt with. After scanning, it turned out to be a loose connection in the heater valve wiring. The workshop found that the cable connector to the water valve was damaged, causing intermittent heating issues. Got it fixed for about 95 Euro, mostly labor costs for diagnosing and repairing the connection. Before you head to the shop though, could you share: Which specific error codes you're getting? Does the heating work better at higher RPMs? Are you noticing any coolant loss? This info would help confirm if you're dealing with the same issue I had. Honestly, with heating problems, it's best to get it checked soon before it potentially leads to bigger issues.

Thanks for the detailed response! I'm having the exact same symptoms with my 7 series (199096 KM on the clock). The heating does work slightly better at higher RPMs, and I haven't noticed any significant coolant loss. Got error codes P0597 and P0598 during the scan. Your experience with the loose connection issue is really helpful, seems less scary than what I was imagining. Did your BMW also make a slight clicking noise from the dash area when switching between temperature settings? Just want to make sure I'm not missing anything before heading to the shop. Thanks again for sharing your repair experience!

Hey again! Yes, I remember that clicking noise very well from my BMW, it's exactly what I experienced when adjusting the temp settings. It's actually quite common with these models. Looking at those error codes (P0597 and P0598) and the symptoms you're describing, it's definitely similar to what I dealt with. The clicking sound comes from the water valve trying to adjust but not getting proper electrical signals due to the wiring issue. When my car was acting up, it made that same noise, especially noticeable during temperature adjustments. With your mileage being around 199K, it's about the same range where I started having these issues. One thing I didn't mention in my previous response, after getting the wiring fixed, I also had them clean the valve housing since there was some buildup. Made a noticeable difference in the heating performance. Just make sure when you take it in, they thoroughly check the wiring harness around the valve area. In my case, they initially just wanted to replace the entire valve unit, which would've cost way more. Glad I insisted on checking the connections first! Let me know how it goes, always curious to hear if others with similar BMW issues get the same resolution I did.

Thanks so much for the additional info, that's really reassuring! You've basically described my car's behavior to a T, especially that bit about the clicking noise. It's actually a relief to hear that you faced the same thing and it wasn't a major repair. I'll definitely take your advice about having them check the wiring harness first before replacing any parts. Was starting to worry I'd need to spend a fortune on a new valve unit, so knowing it might just be a wiring issue is a huge relief. I've already called my mechanic and booked it in for tomorrow morning. Will make sure to mention the wiring connection issue and the valve housing cleaning you suggested. I'll follow up once I get it sorted, really appreciate you taking the time to share your experience in such detail. It's made me feel much more confident about handling this!