Electrical problems
 

I've been having problems with my radio, it would play on and off. I sent it back last week and just as an experiment tried putting in another radio. It does the same exact thing (oops). Then I started to play around with a multimeter after blowing a few fuses, I realized there was current in the body. Theres the reason for my radio not working, it was shorting out everytime the radio would touch the body. Any idea where to start troubleshooting? Any kind of advice would be great, I know the leak could be anywhere and I have absolutely no idea where to start. Thanks