09 prostar electrical problem

Recently purchased an 09 Prostar with ISX 15 and 13sp. I'm having trouble with a direct short on circuit breaker F4-E. says radio fuse. unplugged radio and still have the same problem. Not sure what else this feeds. I have an abs and traction light, no air horn, and no radio. Where are the best places to look on this truck for rubbed through wires? Or maybe something else fed from this circuit breaker that may be bad?

 

no power antenna.
already ruled out everything that is connected to radio.
has to be something else connected to F4-E fuse.

 

ok
there is no cb in it at the moment.
unhooked the radio
unplugged the steering wheel controls
unhooked the 2 large bulkhead connectors.
still pops the breaker immediately.
Anything else listed the feed wire might go to before I start opening up the harness?

 

found it. hot wire melted inside plug on radio just enough it was touching the ground wire.

also traced wire from breaker to radio and it only goes to the radio and nothing else.

I appreciate the help anyway.