[barnstuf]

I am unsure if what I describe is your problem but it might be. At a period of time say 10 or so years ago a major supplier of the horn and headlight loom from the base of the steering column wound the cover material over the individual wires too far toward the bakelite switch plate. This meant the individual wires had no room to flex a bit. This affected the contact for the horn in that the spring loaded contact at the end lf the rod could not mate exactly with the contact on the loom. Often it would go to the side instead of face to face contact. The solution if that is the problem is very simple. Use a razor blade and cut back a few inches on the loom cover material that is woven too close to the plate so the wire to the horn contact can move a bit.