The air bag and horn button I am 99% certain are one assembly and you should just replace it as a unit. I don't know why the steering column would have to be replaced for this issue, should just be the air bag assembly. Use every safety precaution when working on the air bag system. Disconnect battery for around 5-30 minutes (I usually just wait the 30 to be safe). Pull both the tabs on either side of the wheel, and I believe they're 8mm bolts, once those are out the assembly will come right out, there's a connector in there for the horn and the air bag, take care to remove those safely as they can be delicate. If you have buttons on your wheel there will also be connectors for those as well. Installation is reverse of removal. Make sure both bolts are hand tight before tightening them down and make sure no wires are going to be snagged or pinched or prevent operation of the steering wheel in any way during reassembly. When reconnecting the battery, as a safety precaution, make sure no one is directly in front of the air bag. Also, when handling the assemblies, always ensure the ford emblem is facing up, and away from anything important when placing the assembly down in case the bag would deploy accidentally.
