Right Passenger Side Outer Tail Light Lamp Bulb Carrier Socket Holder with Wiring Plug Harness Fit for BMW 3 Series 63217313044

This is a known issue. It happened to my 2014. The ground pin of the tail light bulb holder assembly overheats and eventually loses continuity. For a while it'll be intermittent while you're driving and hard to replicate. There are a couple ways to solve it but I choose to replace the assembly and splice in a new connector. It's fairly simple if you're comfortable splicing wires. Here are the parts I used: https://www.amazon.com/dp/B0BCK9H2ZM https://www.amazon.com/dp/B09WQY83YN