If the battery has shorted out it's probably knackered, but then nothing else would work either. So It might be simply just a fuse that's blown for the radio. The handbook tells you which fuses are which, and where they are. 

This is a very old post by the way ????

The thing is how old is the battery if its more than 5yrs I would replace --

and why did it short out what caused it to short out ????

The battery  its self ???