The Horn mounts to a boss on the exhaust manifold if a single, to the firewall if there are two horns (Hi/Lo tone).
http://good-times.webshots.com/photo/2509864860102454676YABHOn
The entire switch assembly for the horn is shown below.
http://good-times.webshots.com/photo/2377964070102454676NwgCMi
The spring with plastic collar goes into a recess in the steering wheel and contacts the mast bearing (horn wire is attached to it). The horn wire comes out of the column under the dash here.
http://good-times.webshots.com/photo/2980430340102454676PPNeLa

1950 Chevrolet 3/4-Ton 3600
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