1994 Chevy K1500 Bad Wiring?

Ok... I recently bought a 1994 chevy
k1500... just recently I noticed my brake
lights aren't working as they should..
here is a list of odd things... that may or
may not be related....
-Stop light fuse blows
-Brake lights (meaning both rear bulbs
bright) are always on.... with or without fuse
as long as the headlights are turned on, but
tail lights, blinkers, n reverse lights are all
good.
-Stop Fuse blows intermittently. Some
times you can put the fuse in and it'll be fine
til you touch the brakes. Sometimes it'll
blow right away. I've even disconnected all
the rear lights at the wiring harness in back
and get the same results? Anybody think
they can possibly help... will be working on
it for the next few hours... please n thanks