Horn not working

V8 two wheel drive automatic 165,000 miles.

I am having problems with my horn. I have tested the horn under the hood and they work. I have checked the fuse and it is fine. The dealer says that there is no relay on my model. In the past (this has been a problem for three years) I would take apart the steering wheel and clean the contacts on the horn assembly and it would work but only for a short time. Now I cannot get anything to work. Please help.