1954 horn wiring

[certjeff1]

I have a 1954 Mercury in my shop that was torn apart 10 years ago. I am installing the new wiring. The horn ring wire that goes down the column is missing. Where does it come out to meet with the wiring under the dash going to the horn relay? The owner did not take any pictures and does not remember. He does remember the horn working before tearing apart the car. Running my hand down the column I do not feel any obvious openings.