Dave, I finally figured out the problem.
On a 73 ford the relay is on the fenderwell next to the solenoid.
On a 79 ford with cruise, the relay is mounted behind the dash board.
My collum was sending the hot signal to the relay under the dash. The relay under the hood was getting the signal to blow. I plugged the relay under the dash in. Then put a spade connector in to the plug under the hood that tells the horn to blow. Then run a wire to my horn. Now it works great.
Mike.