Actually, fuses do TWO things: Firstly, they protect the wiring, which is the reason not to never short circuit them ("lets use a nail as a fuse-repair"), secondly, they sometimes protect the devices they feed. Sometimes, this can be used to find the fault. Here, the behaviour points towards ... you guessed it, the radio and everything below...
The usual fault finding process is to disconnect all consumers that doesn,t work, and (armed with a suitable number of of correct fuses) reconnect them, one at a time. My best guess: If the radio is a aftermarket installation or the original has been modified, look there first.