firebirdjosh

This is an odd problem and any info such as wiring diagrams would be great. I believe it all started when I installed my radio about a month ago. Tonight, I go to turn on my heater to get some fog off of my windshield and no air comes out. I turn it on full blast and I blew the dash fuse, so now my whole dash doesn't light up. Its only a 5A so I figuered my blower isn't on that circuit. Sliding the vent selector lever makes a few hissing noises which I think is normal, and sliding the temperature lever feels like normal. Its just the air volume **** does nothing. Sounds like a short, but any ideas at all???