[BMBLBEE]

I think the 3rd brake light is several individual LEDs so it's unlikely they would all go at the same time unless you have a short that grounded it out. I would have a very close look at the wires going into the rear hatch to see if there is anything obvious there and jiggle the harness to see if you get any reaction or light from the LEDs. You also might want to pull and change the fuse to make sure there is good contact in that area.

Good luck.