Horn seems to work on cold start, but when driving or idling it does not. Fuse is good. Wipers work. The wires I can see are ok. Trying to get this car inspected (in VA) tomorrow. As long as horn beeps only once for inspector, I'm good to go! I am clueless about cars. This was inherited from someone and seems to be the only thing left to repair ($1500 later!)
It is probably a problem with the horn itself. You might want to check the connection and the wiring to the horn and if you want to test it you can apply battery voltage to it and see if it blows.
Most of the time on these older cars when the horn starts not working it is just because it is too old.