I have a 90 Integra. I am having a problem with my damn horn. The guy that used to own my car put a ghetto looking steering wheel in the car. The horn does not work and he does not have the old steering wheel. When I pull off the center cap of the steering wheel the only wire I see is some black wire hooked up to a round piece of metal and that is it. Is there any wires missing from this?

I need the horn to work so I can get through inspection. Is there any way that I can rig the horn so it will work? I don't even know where the horn is.