Originally Posted by NiVeDh
For E90 LCI tail light retrofit, you need to "re-order" the wiring harness so that it looks like this:
Original credit to this guy who posted wirings.
I have found that few people asked me couple of times about wiring diagrams.
I sent PMs to few and now uploading it, so whoever search it, should come across it.
Please make white plastic clips as reference point (and that should be facing you).
This is from eurooean car (RHD).
OSF (driver side/ Right tail light)
NSF (passenger side / Left tail light)