BMW 4 Heating System Failure, Causes & Solutions Needed

Hey there! I've got some experience with BMWs (been working on them as a hobby). Had a similar issue with my 2021 BMW 3 Series diesel last winter. Initially thought it was just the heating elements, but turned out my battery was seriously drained. The workshop found that the battery couldn't provide enough power for all electrical systems, affecting both front and rear heating. Got it fixed by replacing the old battery, cost me about 290 Euro total, including labor. My mechanic mentioned this is pretty common with BMWs when batteries start failing. But before jumping to conclusions, could you share: Any warning lights on the dash? Does your car have trouble starting? How old is your current battery? Might help figure out if you're dealing with the same problem I had. There's also a chance it could be something else in newer 4 Series models.

Thanks for the detailed response! Just had my last service about 2,000 KM ago, and I'm currently at 85,623 KM. No starting issues at all, and the battery was actually checked during that service, it's the original one that came with the car. The only warning I'm getting is specifically about the heating system malfunction on the display. It's interesting you mention the battery though, I did notice my USB ports seem a bit slower to charge lately. Maybe there's a connection there? I'll definitely keep the battery possibility in mind when I take it to the workshop. Probably best to get it checked professionally before winter really kicks in.

Hey again! That's really interesting what you mentioned about the USB ports being slower. You know what? That's exactly how my issues started too! I initially ignored those small signs, which looking back, were early warnings of the battery starting to give up. Even though your battery passed the service check, these problems can develop pretty quickly. My BMW's battery also passed a check just months before it started acting up. These modern BMWs are super power-hungry with all their electronic systems, and sometimes the battery can be right on the edge of acceptable but still cause these weird issues. From what I learned with my car, even if the battery seems fine for starting, it might not be providing enough consistent power for all the auxiliary systems like heating and USB charging. The heating elements in particular need a good amount of stable power to work properly. I'd definitely push for a thorough battery test when you take it in. My mechanic used a specific load tester that showed issues the regular service check missed. Better to catch it now than end up stuck with a completely dead battery later! Let me know what they find, would be good to know if it's the same issue I had or something else entirely.

Thanks so much for the follow-up info! That definitely makes a lot of sense about the progressive battery issues. I've actually booked an appointment at the workshop for next week, your experience has convinced me to specifically request that thorough battery load test you mentioned. Really appreciate you taking the time to share your experience in such detail. It's saved me from potentially just focusing on the heating system alone, which might have meant missing the real underlying issue. Will update you once I get the diagnosis. Thanks again for all your help!