Uhm...when you turn your radio on and off does it make a weird noise?

Do you still have your factory radio or have you replaced yours recently?

Done anything in your cars interior, i.e. remove panels or cut wires?

You may have pulled the plug off or knocked the wire loose. If you put in a new radio you may not have hooked it up at all. Or there's a chance (although I'm not too sure) that there may be a fuse for that...check the fuses too.