Z3 Battery Woes: Warning Lights and Starting Issues

I had almost identical issues with my 2005 BMW Z4 last month. The battery sensor was indeed faulty, causing similar warning lights and starting problems. Initially thought it was just a dying battery, but the diagnostic showed the sensor wasn't correctly measuring the battery's charge state. Had it fixed at a certified BMW shop. The repair involved replacing both the battery sensor and its wiring harness since there was some corrosion at the connection points. It wasn't a major repair, but definitely not something to ignore as it can lead to unexpected breakdowns. The mechanic explained that these sensors are pretty common failure points in BMW vehicles from that era. My car's got about 62000 KM, so pretty close to your situation. Make sure whoever works on it uses the right diagnostic tools, that's crucial for these sensor issues. The fix sorted out all the symptoms, no more warning lights, strong starts, and normal lighting. Just get it checked soon before it leaves you stranded somewhere.

Thanks for sharing your experience! Really helpful to know I'm not alone with this issue. The symptoms you described match mine exactly. Got it booked in at a specialist shop next week. Hey, do you remember roughly how much you ended up paying for the whole fix? And has everything been running smoothly since then, or have you noticed any other electrical quirks?

Hey again! Glad I could help! Yeah, I remember exactly what I paid, it was 315 € for the whole job, including the new sensor, wiring, and labor. Honestly, it was worth every cent because the car's been running like a dream since then. No more warning lights, no dimming, and she starts up perfectly every time. It's been about 6 weeks since the repair, and I haven't noticed any other electrical issues at all. The mechanic did a thorough job and even cleaned up the battery terminals while they were at it, which was a nice bonus. You definitely want to make sure they use proper diagnostic equipment, my guy showed me exactly what was wrong on the computer before starting the work. Just keep in mind that with these older BMWs, it's super important to get these electrical issues sorted quickly. I'm really glad I didn't wait around on fixing mine. Let me know how your repair goes next week, I'm curious to hear if they find the same issue!

Thanks so much for the detailed info! Just got back from the shop today, and you were spot on about everything. The mechanic found the same issue, faulty battery sensor and some corroded wiring. Ended up being a bit pricier at 380 €, but they also did a full electrical system check while they were at it. The whole experience was way better than my last mechanic. These guys actually showed me the damaged parts and explained everything clearly. No more warning lights flashing at me like a Christmas tree, and the engine starts up beautifully now. Such a relief! Really appreciate your help with this. Saved me from going crazy wondering what was wrong with my Z3. Sometimes it's just good to hear from someone who's been through the same thing. Time to enjoy some proper drives without worrying about getting stranded!