I don't know if this will help anyone or not. I spent the best part of 3 hours trying to figure out why my tail light was not working, but the brake light was fine. I had one blown fuse, a 5 amp, and one that was good (#10 and #8) I put the good 5 amp in #8 and the tail light still did not work. After quite a bit of looking for shorts and whatever, I finally figured out that the tail light MUST have both #10 and #8 fuses to work

It sure did not make since to me and still doesn't, but thats the way it works.