Your picture is too small to be of any help. The horn button is the ground. The S wire is supposed to make contact with the side(s) of the hole(s) in the steering wheel while, at the same time, making contact with the copper strip on top of the steering mast bushing. This contact completes the ground and honks the horn.

Put the steering wheel on the mast, remove the S wire from the rubber bushing and slide the S wire through the holes until it makes contact with the bushing while also touching the side of the hole(s) the legs of the S wire pass through. That should cause the horn to blow. If you have to wiggle the S wire around to complete the circuit and honk the horn, your contacts on the bushing and/or the edges of the S wire holes are dirty and preventing the contacts from touching. That whole set-up is problematic. There was a period accessory one could buy the consisted of a small metal plate with ears that connected to the S wire and a small spring on the flat of the piece of metal. The spring would ride against the top of the steering mast and would make more positive contact when the horn button is pressed (not depending so much on the sides of the S wire making contact with the sides of the holes). I suspect one or more of the contact points is dirty/corroded and preventing the circuit from closing.

Here are a couple of new pictures hope this helps.

Hello Michael McDonald,

Tiny has you covered with his post. Here is what i'll try and add. Your horn button test without the steering wheel installed, must have had a ground that you provided for the test, i'm thinking. Then, when the steering wheel was installed, the test failed. You should shine-up every potential ground as advised. Don't forget to clean the mast bushing contact surface also. Consider, maybe the distance between mast bushing and steering wheel could be too far apart for horn button legs to make contact. Don't know, just a guess. Check out VCCA old forum: (title) How Does The Horn Button Work? by Bare Feet 12/01/16 02:33pm #379599.

Link to the thread.

FWIW I added about a 1/16" of solder to the ends of the legs on my S wire so I don't have to push the button in so far to make the horn honk. I started with 1/8" and ended up taking some off to get it "just right".

I did use a ground wire the first time with the wheel and horn button off. It was the woodruff key it fell in the gap. After we removed it we used a ground wire.

I will clean everything and see if I can make it work.

Thanks again for all your help. After removing the steering wheel several times and cleaning and sanding I finally got the horn to work. Now I guess you can say I can toot my own horn.

I know this is an old topic, but I too have had an issue with the whole bushing install, where my horn would honk on it's own and I sometimes couldn't get it to stop.  I know the issue is likely the bushing isn't pushed down far enough, but that's my question, how far do I need to press the bushing in?  Seems like there is a stop tab in the column, do I bottom the bushing out on the tab?

BTW, this is in my 38 MD Business Coupe.

@bryan-toedtli

Hello Bryan Toedtli,

You should read the link to: How does the horn button work? Think about getting a copy of April 1930 issue Chevrolet Service News or looking for a 1938 Chevrolet Repair Manual. There may have been some design changes made between 1930 and 1938, so you should default to 38. The horn system may be similar in design but measurements may be different. If your horn button depends upon its rubber part to 'spring' back and pull grounding legs up and away from mast bushing contact ring, that rubber may be deteriorated enough to fail its job. Or as you say, mast bushing may not be in its proper position. Overall, review the Manual for your vehicle to know what you're looking for.

This may help. It's a thread from the old forum. <CLICK ME>

@bryan-toedtli On my 32 the horn button return rubber was "lazy" and did not always return properly. I used a childs sponge rubber ball and cut it to fit inside the horn rubber and it now returns to the correct position and still works fine.