suburban heating and cooling problem

I have a 98 suburban, the problem I have is that the cold and hot air comes out only from the vents in the windshield. It seems like the controls are not working. I can not regulate or control it with the knobs on the front pannel. I'm able to control the heat and cold intensity but not the circulation from the front side air ducts nor the floor ducts. I need to know if I need to replace some sort of fuse or get a replacement part and what that part is. The problem started right after I installed a new radio. Could it be that I didn't reconnect a wire that controls those functions?

Sounds like some wire (maybe the antenna cable) is blocking the door from closing so the air is not getting down there. I would take the radio out then try the AC and heat and see if it works before putting it back in.