BMW Z3 Door Handle Causing Electrical System Havoc?

Hey there! As someone with some experience working on BMWs, I had a similar issue with my 2003 BMW Z4 last year. Actually, my friend also went through this with his 325i. The symptoms were exactly like yours, keyless entry completely dead and those pesky battery drain codes. Turned out it was indeed a faulty connection in the door handle wiring. My mechanic found corroded cables and a loose plug connection to the door handle module. The repair was pretty straightforward, they replaced the wiring harness and connection points. Cost me about 95 Euro and it's been working perfectly since then. Before jumping to conclusions though, could you share: How long has this been happening? Have you noticed any moisture damage around the door handle area? Are you getting any specific error codes you could share? This would help me give you more targeted advice based on my experience.

Thanks for the detailed response! I've had my Z3 for quite a while (38645 KM on the clock since my latest service), and this problem started about two weeks ago. Actually, I did notice some water marks inside the driver's door when I checked yesterday. I'll get the exact error codes from my scanner tonight and share them here. Really appreciate the tip about the wiring harness, that's super helpful and definitely sounds similar to what I'm experiencing. Was your repair done at a specialized BMW shop, or did a regular mechanic handle it? Just trying to figure out my best option for getting this fixed.

Hey again! Glad to help further with your Z3 situation. Since we're talking about the same issue I had with my Z4, I can definitely relate to those water marks you found, that's exactly what I discovered in mine too! Actually, for my repair, I ended up going to a regular independent mechanic who specializes in European cars. The BMW dealership quoted me nearly triple the price for basically the same work. My trusted mechanic had dealt with these door handle wiring issues before, so he knew exactly what to look for. One thing I didn't mention in my first response, before getting it fixed, I tried drying out the door panel with a fan and checked all the rubber seals. Didn't solve the problem, but it's worth knowing that water intrusion is usually the start of these issues. With your mileage being similar to what mine was when this happened, it's pretty typical for these seals to start failing. Quick tip based on my experience: when you get it fixed, make sure they check both door handles, even if only one is showing problems. In my case, the other side started showing similar issues about two months after fixing the first one, so I ended up having both done. Saved me a second trip to the mechanic! Let me know what those error codes show when you get them, I still have my old ones written down somewhere if you want to compare.

Thanks so much for the follow-up advice! This is incredibly helpful information, especially about checking both door handles. The error codes I just pulled are FE36 and FE42, which from what I understand, relate to the electrical system and door module issues you mentioned. I definitely want to avoid dealership prices if possible, and your experience with an independent mechanic is reassuring. I've got a local European car specialist that I'm thinking of trying, good to know they should be able to handle this kind of repair. Smart thinking about the rubber seals too, I'll have them check those while they're at it. You're saving me a lot of headaches with these tips! I'll probably go ahead and get both door handles checked out at the same time, just like you suggested. Better to fix everything at once than make multiple trips. I'll keep you posted on how the repair goes, thanks again for sharing your experience with this!