Seat Mii electrical issues

I have a Mii too. Sounds like you're experiencing something similar to what I had a while back. Did you try using a scan tool to check for any stored error codes? That might give you a better idea of where the problem lies. Also, is the warning signal constant, or does it come and go?

Yeah, I used a basic scan tool, and it showed a bunch of errors, mostly related to the audio and navigation, but nothing specific. The warning light comes and goes, sometimes it's on for days, sometimes it disappears for a week. What was the specific issue you had, and how did you fix it?

Yes, the symptoms you describe are very similar to what I experienced. The error codes were misleading in my case as well. I would suggest taking it to a workshop for professional engine diagnostics. It is likely a defective cable connection of the control unit, specifically the connection to the BUS system. This can cause all sorts of seemingly unrelated issues due to communication problems between the control units.

Took it to the shop, and they found a defective cable connection to the BUS system. Seems like that was causing all the weirdness. They charged me 155€, and everything seems to be working fine now. Thanks for the help!