I did a dashboard restoration last year and when I finished, I had a horn issue. When I put the steering wheel together and turned the wheel, the horn would blow. I disconnected the relay and planned to pull the steering column and replace the brass ring on the shaft. There are some great articles on that here!
Yesterday I was putzing around with the hand brake switch and I my eyes focused on the NSS. I read an article about the spring loaded horn button in the NSS. I removed the bolt holding it on the column and took a picture of the wiring for reassembly. I took the assembly to my workshop and disassembled and cleaned the unit. I saw the prices of NSS’s on Ebay and was extremely careful working with it.
The horn button was in relatively good shape. There is a good article on remaking the button that i read. It was still round and had plenty of meat on it. I cleaned it with steel wool and sprayed everything down with contact cleaner and switch lubricant.
I took my ohm meter and put the probe through the hole in the top of the steering column. I found that only a section of the ring was making contact with ground. It appeared that if I adjusted the NSS down toward the gear box a bit, it would miss the grounding section of the ring.
I stuck scotch bright in the hole and spun the wheel to clean the brass ring. Did not use steel wool fearing metallic dust would be bad! I remounted the NSS and used the ohm meter to detect grounding (better than the wife yelling at me about the horn blowing!). I was able to move the NSS down and spin the spring loaded button to find a place where it did not ground out! Success!
Aligning the NSS to provide backup lights, allow starting in N and P, and not blowing the horn took about an hour! It works great! Time will tell if the horn is really fixed.