Is to trace the original wire, if you can, and then plug another wire in exactly the same place. If the radio still doesn't work, it's either the fuse box or the radio. If you lightly and quickly ground the new wire to something else (without blowing the fuse, just super fast rub it past some metal, like the brake pedal stem) while still having the other end in the fuse box, you need to see some sparks. If you don't, something's wrong with the fuse area.

Even if a fuse looks good, it still may be blown. A very small crack in it will stop current.

If all that works, it's probably the radio. Replace it.

Hahahahaaha