1995 Buick Century Buick Century Brake Fuse Blows When Head

Hello gentlemen. I have a 95' Buick Century. Whenever I turn the headlights on the fuse for my brake lights blows out. The brake lights and running lights stop working along with dashboard and interior lights. There is an after market stereo installed and the headlight switch has been replaced with a new one from the dealer. Any help is greatly appreciated especially if you can upload a wiring diagram. Thank you.