mute speaker help
 

I have a 420 SEL with the stock stereo and all four speakers have gone mute on me. I am hoping this could be a quick fix and was wondering what the possible causes are. The radio itself works, all buttons work and i can change stations, but no sound is produced on all speakers. I was wondering whether the connections behind the radio became disconnected/fried or if something with the fader is causing this, because the fader had not been working very well for the past few months. I am contemplating replacing the radio and speakers, but am really hoping that the wiring doesn't need to be replaced.
Thanks

You got an external fader? (on the console somewhere)

That's the first place to look.