Originally Posted by Razorclaw

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!