a friend of mine needed help jumping her car and the wrong person helped her. he reversed the wires when he was jumping the car. now the fuse for the radio keeps going bad as soon as i put it in. what can possibly be wrong with the car.

 

it means that fuse is constantly overloaded. something on that line has shorted out, may be a melted wire or melted wire coating somewhere between that fuse and the battery. good luck.