Left rear tail light will not work anymore?

Check the ground at lh rear frame also check connection on circuit board may be a bad board its on very rear cross member with all light harness going to it

I don't think it will be the ground at the frame because both sides use the same ground. I would recheck the tail light housing electrical connector for burns or corrosion. Here is the tail light and blinker wiring diagrams so you can see how the system works. The blinker and tail lights have there own power circuits so it would be rare for them both to go out. Check out the images (below). Check the fuses in the wiring diagrams as well.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let us know what you find.