this isnt for my firebird but for my buddys altima, but im not about to join a altima forum for this. the deck works its not faded all the way back or anything, only the rear speakers have sound the front doors dont nor do the tweeters, no blown fuses? he got the car like this? what would cause it? i would like to try and fix it today.

 

I was going to say to make sure it wasn't turned to the back speakers.
Could just be a bad radio.
I wouldn't think they would all be bad, could just be that the previous owner disconnected them.
My camaro had the rears not working, I think they were connected, but not right.
Hooked them up thru the factory wires and it was fine. The kid I bought it from had a system, and I think I have enought wires left to competely wire my 49 Ford.

Point being, pull the radio, and if you need to the speakers, make sure the wires are hooked up to the radio, then to the speakers, and make sure you are getting power to the speakers.