BMW Z3 Aux Parking Heater Dead, DIY or Pro Fix?

Hey there! I faced a similar issue with my 2005 BMW Z4 last winter. The parking heater problem turned out to be more complex than expected. When I brought it to my mechanic, they found that the glow plug was defective and the control unit was also damaged. The fuel pump wasn't getting proper signals. They had to replace both the glow plug and the control module to get the system working again. It wasn't just a quick fix, they needed to run several diagnostic tests to pinpoint the exact problem. Took about two days to get all parts and complete the repair. This was quite a serious issue since the parking heater is a complete auxiliary system, and when it fails, it needs proper diagnosis. My advice would be to find a mechanic who specializes in BMW auxiliary heating systems specifically, it's not something every general mechanic deals with regularly. Best of luck getting it sorted out!

Thanks for sharing your experience! It's helpful to know what you went through with your Z4. Been wondering about something though, would you mind sharing how much the whole repair set you back? Also, has everything been working smoothly since the fix, or have you noticed any other quirks? Just want to get an idea of what I might be looking at cost-wise and if I should expect any follow-up issues. Really appreciate your help with this!

Hey again! Happy to give you an update on my Z4 heater situation. Great news, after getting it fixed, the auxiliary heater has been working perfectly fine! No more issues whatsoever. The total repair cost was 440 € for replacing the defective glow plug, which honestly wasn't as bad as I initially feared it might be. I know in my first message I mentioned they also replaced the control module, but turns out the glow plug was actually the only thing that needed replacing, the control unit was fine after all. The mechanic did a thorough job diagnosing it, and I'm really glad I went with a specialist who knew what they were doing. The heater now kicks in immediately when I need it, no strange noises, no error codes, it's like having a brand new system. If you're still looking for a fix, I'd definitely recommend getting it checked out sooner rather than later. These things tend to get worse if left alone, and winter isn't the best time to deal with heating problems! Let me know if you need any other details about the repair. Happy to help!

Thanks so much for all the details! Just got back from getting my Z3 checked out, and wow, what a different experience from my last mechanic! Found this specialist who really knew their stuff. Turned out my issue was also related to the glow plug, but I had some additional wiring problems too. Total bill came to around 600 €, a bit more than yours but still better than I expected. The funny part was when the mechanic started it up for the first time after fixing it, the look on his face when everything worked perfectly was priceless! He'd been so focused on getting every detail right. Been running smoothly for a few days now, and it's such a relief not seeing those error codes anymore. Really grateful for your advice about going to a specialist. You definitely saved me from another potentially bad experience with a general mechanic. Think I've found my new go-to place for any future BMW issues!