President headlight switch electrical fault

I had a similar issue with my President! Faulty headlight switch can cause all sorts of electrical problems. Did you check the cable and plug connections to the switch itself? A defective connection there can definitely trigger the symptoms you described. Sometimes it's a simple fix, sometimes not.

Cable and plug connection, huh? Where exactly should I be looking? Any specific wires known to cause trouble?

Yes, exactly that! In my case, the plug connector was partially disconnected. Honestly, these things can be fiddly. Unless you're very comfortable with car electrics, I'd recommend getting it checked out at a workshop. Those error codes can point them in the right direction, and they can test the circuit properly. I wouldn't want you messing with the airbag system if you are not confident!

Appreciate the insight. Turns out it was indeed a defective cable connection. Workshop sorted it for 95€. Thanks!