make sure the wiring to the horn button is still intact, it may have broken inside the column.
In the average/basic horn system setup(not specific for every car though), the horn relay should have full power at 2 of the 4 terminals and then the third goes the the horn itself. the 4th wire comes from the horn button. when you press the horn, it grouds that wire therfore activating the relay. check the wiring to the relay, find the 2 non-positive wires and check to make sure you get a ground signal from one of them when you press the horn button, if nothing, youll have to work your way back through the wiring harness until you find the problem.
Here is a quick schematic i did to explain it better, (i know some objects are not "correct" but its just to give a general idea) Remember the is a general wiring setup, may not be exact to an fbody, but its close.
