When "the guy took the air bag and all the horn stuff under it", he may or may not have replaced the clockspring. That's the flat spool-like device under the airbag. The wires for the horn and cruise switches run through it. It provides slack in the wires so they don't break or get tangled when you turn the steering wheel. If it goes bad, the horn won't work.
But, I discovered another possible cause of the horn not working when I added cruise control to my '02 Sport Trac a couple of months ago. Under the airbag are the horn switches. They have hard plastic on the ends of them. If the plastic breaks like mine had, the airbag can't depress the horn switch far enough to make contact. Fortunately they only see wear and breakage from one end. They can be switched from one side to the other if you flip them over, giving you good plastic on the end that gets depressed when you activate the horn. Easy fix if that's the problem. Just disconnect the battery, remove the 2 screws that hold the airbag in place. Unplug it and set it aside. The horn switches or contacts are the silver metal pieces with a wire connected to their middle. 2 Torx screws hold each one. Take them out, flip the contacts and swap them from one side of the steering wheel to the other, & put everything back together.
