I would be happy to provide the schematic. If you look at the first two pics below, they include the entire schematic for exterior lighting. I had to cut the pic in half to make them readable. I did overlap them.
If you look at pic 3, I highlighted the right rear light, wire to it, and a junction connector (which I suspect is where the problem is) on the left rear.
Here is a link that you may find helpful:
Let me know what you find or if you have other questions
See pics below.
Images (Click to enlarge)
Tuesday, May 4th, 2021 AT 9:07 PM