how to find a short in cranking and brake light's on 1998 Chevrolet 1500 Pickup

truck wouldnt start unless cross out starter solenoid, replaced solenoid, same problem, used a test light to test the crank fuse , when i touched the fuse it turns over and cranks. brake lights dont work with key on, work fine with key on. wheni touch brake pedal with key off gas gauge goes all the way over past full. key on works fine but vibrating a little. any hints ?

Asked by for the 1998 Chevrolet 1500 Pickup