stop light fuse keeps blowing?

hey guys I had a question about my brake light fuse. Everytime I install it, it blows. I have found no open wires, and I am kind of lost at this point. What all does this fuse control ? I figured its the brake lights and dome light, but I can hear a relay click behind the dash as soon as the fuse makes connection, and then it blows. I have also misplaced my manual so I was looking to see here quick if anyone has any tips before i go find another book tomorrow. thanks in advance