Horn issues

[Lattimer]

So, my horn didn't work when I got the truck a month ago. As I have been working through various issues, I've been replacing a lot of parts and fixing all sorts of PO screw ups.

Horn itself was no good, so I replaced with a basic Wolo low tone. Wiring in the engine compartment was half melted and bare in spots so I replaced it back to the firewall. Found the plug at the relay disconnected and melted, so I installed a new relay and spliced in a new plug.

I have also replaced the steering column with a new tilt column and replaced the steering wheel with a new Grant wheel, new horn button, etc., so everything except the under dash harness is essentially new.

If I short across the plug at the relay, I can get the horn to honk. And that is the only way. Shorting the horn button inside the column does nothing, so I think my issue is between the column and the horn somewhere. I'm about to splice into the wires at the column and just run all new to the horn from there and abandon the factory wiring, as I am pretty much out of ideas.

Anybody have any insight as to what else I can look for? Anything hidden under the dash I'm not aware of?