Do you get static and no reception, or literally no sound at all? Did you just install the head unit or have you had it installed and all of the sudden it stopped working? There is an antenna wire that needs plugged in to the back of the head unit. If this isn't plugged in you won't get any reception at all. It's a thick black wire with a single prong on it.
If this isn't the problem then I would venture to say it's something inside the radio.
I went back out there and checked. If you turn it all the way up you can barely hear static and the words. It is working but you can't make anything out. I have never heard a radio do this before so i am lost. It is the factory radio and has not been messed with at all.
Where are you located? If you live near, I can hook you up if you so please.