I put new 14g wire in for both and get 5v at the tail light wire but 0v for the brake with the pedal depressed. I checked the brake light switch which is a new replacement and there is 6v on both terminals with the pedal depressed
Have you checked the ground? My stop/tail light housing was rusted between the metal housing and the bulb holders. Run a wire from a known good ground and re-test for voltage. If you have voltage, you know you have a ground problem.
