For what it’s worth I had the exact same code and problem, 11 passenger side buckle switch. What I did to fix it was spray some electronic cleaner, like CRC or something, I used CRC Mass Airflow Cleaner because that’s what I had around. I sprayed it down the buckle (sparingly) and then latched and unlatched the buckle a bunch of times, then let it sit to dry for a while, then cleared the code with the B800. Lights been off and stayed off for at least a month now
Have the same problem recently. Yes have none of those fancy machines.... take it will need garage job?
You could get a b800 or a code reader of some sort and that would tell you exactly where the problem is, then repair/replace the faulty part, then clear the code to make the light go out. Or take it to a mechanic, that is what they will do. I “fixed” mine by cleaning the switch, but eventually the light came back on. I will need to replace the latch buckle thing I think
There are a number of "Zed Shed's" around the UK which are associated with this forum. These are groups of Z3 owners who meet regularly on the weekends and fix their cars together. They know the Z3 well. Maybe there is one close by and the guy's there can scan the car and maybe fix it.
