How to replace steering wheel, connect horn

[Austin C10]

Here's my problem. The recent owner of my 1972 Cheyenne replaced the steering wheel with a little cherry wood wheel. There is no longer a horn switch anywhere in the cab. My inspection sticker was stolen, and I failed inspection b/c of the missing horn switch.

I have 2 horns and followed the green wire from them to the firewall.

Where do I go from here? I'm sure everthing will be more evident when I get the wheel pulled off. I'd like to replace the steering wheel and reconnect the horn.

Obviously, I need a new steering wheel. I found a nice wooden Grant's and a plastic reproduction. How do I determine what else I need to reconnect the horn switch on the new wheel?

I was unable to trace the horn wire through the underdash harness. I found the relay box, but couldn't trace from there to the steering column. Basically, I want to be able to trouble shoot this if replacing the steering wheel, horn button, and connecting to the horn cancelling cam doesn't work. Where can I get a good diagram of the horn wiring?

Thanks!