Noticed right rear small red light just above reverse light not working when I hit the door unlock button while walking up to my car last week. No i-drive codes. On closer inspection, the bulb was working, but only at about 10% intensity.
I changed the bulb myself with a P21W bulb purchased at the dealership ($10). No difference.
Read this post.
Took apart tail light assembly (5 minutes) and pulled the wiring harness connection out. There are 7 wire connections. #5, the brown wire, had melted plastic surrounding the connection for about a 2 mm radius. Screwed with it for a few minutes, plugged it back up, and now everything working well.
Appointment at dealership for wiring harness replacement under warranty in two days.
Thanks for the help on this Nube1kenobi!
2010 550i Sport