Hey guys, I've got a wiring/lighting issue I was hoping somone could help with.

Whoever had the car before me, I'm guessing the brake lights went out on him. Whoever tried to fix it for some reason spliced into the power wire leading into the hatch brake light. They then proceeded to run that wire into the brake lights so that they can run lights. The problem that I have is that with the way they did it whenever I press on the brake while the tail-lights are on the light barely gets any brighter. Any ideas on what I should do to fix it? I'm not sure if it makes it to where the brake lights are always on or if it just doesnt get hardly any brighter when I press on the brakes.
Also, whenever the lights are turned off and you press on the brakes, for some reason the dash lights light up.
It's a 96 Z28

Thanks for the time!