BMW i8 Hybrid Alarm System Dead, Siren Issues Help

Hi there! I have some experience with car electronics, and I faced a very similar issue with my 2017 BMW i3 (also had an i4 before). The alarm system completely died on me last year, exact same symptoms as yours. Took it to my regular workshop and they found it was just a loose connection in the siren wiring harness. Apparently, these plugs can get corroded or work themselves loose over time. The fix was pretty straightforward, they cleaned the connections and secured them properly. Cost me 95 Euro and it's been working perfectly since then. Before you head to a workshop though, could you share: Have you noticed any other electrical issues? Did this happen suddenly or gradually? Are you getting any other warning lights on the dash? This could help narrow down if you're dealing with the same problem I had. These hybrid systems can be tricky, so it's best to get all the details.

Thanks for sharing your experience! Mine just hit 134620 KM and had its last service about 2 months ago. The issue started gradually, first the beeps became inconsistent, then stopped completely last week. No other electrical problems or warning lights so far. You might be onto something with the wiring, makes sense since we've had some wet weather lately. I'm hoping it's just a connection issue like yours and not the entire siren unit. Will definitely get those connections checked first before going for any major repairs. Thanks for the tip!

Hey again! That's exactly how mine started too, the inconsistent beeping was definitely a red flag. Since you mentioned the wet weather, I'm even more convinced it's similar to what I experienced with my i8. The gradual failure pattern matches perfectly with what happened to mine, it's actually quite typical for moisture-related connection issues. And the fact that it's right after some wet weather really strengthens the loose connection theory I mentioned before. In my case, there was also a bit of corrosion build-up on the connectors that the techs found when they dug deeper. Given your mileage (mine was around 120000 km when it happened), it's about the right time for these kinds of issues to show up. Quick tip though, when you take it in, ask them to check the siren's mounting points too. While they were fixing mine, they noticed the rubber grommet that helps keep moisture out was slightly degraded. They replaced that as well, and I think that's partly why I haven't had any issues since. Let me know how it goes when you get it checked out. Always good to compare notes with fellow i8 owners!

Thanks so much for all the detailed info! Really appreciate you taking the time to explain everything. That's super helpful about the rubber grommet, definitely wouldn't have thought to ask about that. I've already called my mechanic and booked it in for tomorrow morning. You've actually saved me a lot of worry, I was stressing about needing to replace the whole alarm system, which would've been way more expensive. Knowing that yours was fixed with just a connection cleaning and grommet replacement makes me feel much better about the whole situation. I'll update you once I get it back from the shop. Thanks again for all your help, it's great to have such knowledgeable i8 owners to turn to for advice!