When I bought my new old '52 GMC 150 truck in March I noticed that the horn (among other things) didn't work. Additional inspection uncovered one of those generic after market horn buttons screwed to the bottom of the dash. Pushed it and BEEP. Good enough for the moment. A couple of months ago I removed the stock horn switch from the steering wheel and did some basic ohm meter testing. Found that the switch was shorted, which would result in a constantly blowing horn, thus the previous owner had the generic switch installed. I ordered a replacement switch from our host Classic Parts and just set it aside when it arrived. I am now in the midst of a bunch of under-dash work (electric wipers, new cowl vent gasket, radio and proper ignition switch) and decided that this would be a good time to ditch the generic button and get the horn working as General Motors intended. Removed the steering wheel, cleaned up the brass contact ring at the top of the steering column, checked for continuity from the horn wire to the ring (0.002 ohms), cleaned up the brass contact on each end of the spring loaded gizmo that goes through the steering wheel, mounted the steering wheel, the gizmo, the new switch, the flat washer, lock washer and the nut. Tried the ohms test again, this time between the horn wire and ground. Damn! No connection when I pressed the horn button. Took it back apart and tested each component individually. What I found was .... The black portion of the new switch has a coating (paint?) on it. When the horn button is pressed this black piece moves down and contacts the silver piece on the underside of the switch. Contact is made near the outer edge of the two pieces. The bad news is the black coating does not conduct electricity, therefore no BEEP. I "fixed" the problem by putting a piece of 240 grit sandpaper between the black and silver pieces (grit toward the black piece), squeezed the black and silver pieces gently together and moved the sandpaper to knock the coating off of this area. Did this all the way around the edge of the switch. Now my beep is working as designed.