Stop Light Fuse keeps blowing

Hello all. I'm having an issue with my brake system.

Symptoms:
1. Won't shift out of park without override
2. Stop light fuse pops repeatedly (replaced 4 times)
3. Replaced Brake switch but problem still exists
4. Brake pedal began sticking today.

I have read that it could be an electrical short but I don't have the first idea how to track it down. Any advice on where to begin?
Could the brake pedal sticking be related to improper installation of the new switch or related to the possible electrical short?

FYI: A)There is an aftermarket tow hitch and wiring that were installed about five years ago by the previous owner. B)I live in the desert and drive a lot of bumpy dirt roads. C)I replaced the rotors and brake pads in August.

I do all my own repairs as I refuse to pay a mechanic to do something I can do myself.

 

try unplugging/removing the hitch wiring. i have seen the converter boxes go bad and blow fuses