electric problems

[phantom dually]

That box is actually just a inline noise supression filter. The best thing to do is to get a test light and ground in to the chassis of the radio with the antenna unplugged. Turn the key on to see if you are getting 12v to the switched wire and to the constant power wires. If you are getting both then the radio is toast. If you are getting 12v to one and not the other then take the wire that is not getting power and tie it into the on that is. This will tell you if the radio works or not. If it does work this way there is a reason you are not getting power to this wire and almost has to be a fuse.