How can you short a wire on a car Stereo without breaking the stereo?

I have a Power Akoustic in dash CD/DVD stereo and i can't watch movies on it. I don't have the brake cable hooked up, and you can't watch movies while the car is driving but i was told that you can short the brake wire and then be able to watch movies anytime....i mean come on whats the point of having one if it can't play movies and videos right?How can you short a wire on a car Stereo without breaking the stereo?
you can run a wire from your positive side of the battery, to the inside of your vehicle, through a hole behind the dash board, its gonna have a rubber gasket or something like that, then attach the wire to your cd dvd player's brake cable, and it will play anytime. How can you short a wire on a car Stereo without breaking the stereo?
I think any 12 vdc source should be fine. Try and find your ACC wire in your ignition switch and tap that wire that way your player will think that car is in park whenever you start your car or have it in the ACC position.