Stereo HELP!!!

[84chevysilverado]

I have a 1984 chevy silverado and I'm having radio/stereo issues. Everytime I drive the truck the radio shuts itself off or when I brake. I thought it was a loose wire or a loose connection. Everything is hooked up correctly however when I checked where the stereo was connected to the fuse box the previous owner had it hooked up to the hazard/stop lights. I am assuming this isn't a constant connection and moved it to the 'RDO' one and it still does the same thing!! HELP!!