When I bought my truck it did not physically have a horn on it. It also had an aftermarket column that was missing a bushing that would have prevented the horn from actually working if it had one. I replaced the column with a new aftermarket column that uses a 2-wire horn button with one wire grounded to the steering wheel hub and the other wire connected to the Blue/Yellow wire labeled #1 on the wiring diagrams. The wiring on this truck has been mucked with a good bit before I got the truck. Under the hood, the Blue/Yellow wire was cut off after the junction near the starter relay and not connected to anything. Also at the junction near the starter relay, the Yellow (#33) wire was directly connected to the Yellow/Green (#6) wire via a butt splice, with the other end of the Yellow/Green wire just loose not connected to anything. I bought a HR127T relay thinking I needed one as per the wiring diagrams but after reading several threads here, not sure I need it. I bolted the horn to the stock location on the core support and connected the Blue/Yellow wire directly to it but when I pushed the horn button...nothing happened. Not sure how this should be wired up at this point.

 

You should be using a relay, without it you will probably burn up the wiring to the column. The power for horn is draw directly from the battery via connection at starter relay. The horn button shorts to ground activating the horn relay. Make sure in the new column that the ground is connected for the horn. Here is simplified schematic from a earlier year. It's similar to what your working on but easier to read.

https://www.fordification.com/tech/wiring/68-17.jpg

 

Thanks for the link...it was very helpful. Not sure why some of the posts on this topic say you only need the relay when your vehicle has speed control. I guess you could eliminate the relay if your horn was grounded by a second lead on it instead of the mounting bracket and the Yellow/Green wire was connected directly to the Yellow wire and you connected the Blue/Yellow wire to the second lead to provide the ground when the button was pressed. The one thing that was throwing me off was the diagram on the side of the relay. If they would add a ground symbol to the diagram for the trigger connection it would have made a lot more sense...at least to me. Horn working now...just have to make the permanent connections and tie it all up.

 

The horn pulls a lot of amps the reason for the relay. The small 20 ga wire ran for the horn to the column can not handle the load. Would get a lot of arcing. In the today's digital world relays are widely used.