1952-59 Ford 1956 horns

I thought I had lucked out when I connected each horn to a 12 volt battery and they honked a couple of times. Well, my joy was short lived. The only make a tiny clicking sound now. No more honking.
I opened them up and blew out a bit of dust. Both horns have SPARTON stamped into the cover.
Has anyone run into this and found out how to make them work again?

 

Take them off and test them again. If they work then I would check the relay.

 

They are off and connected directly to the battery on the bench.

 

I know this is basic stuff here, but you do have positive to positive, negative to negative, correct? Not sure if it makes a difference on these, but it did on a pair of aftermarket ones I bought. It seems odd they both worked, and now they both don't. are you sure your supply battery is good?

 

tried both + & - ground. just a little click. Has anyone found a way to make them work? Problem seems to be in the horn itself.

 

There is a "point-like" contact in the horn. How are these to be gapped? Any ideas?

 

Have you tried cleaning the points?

 

points are clean. there is a resistor in the horn. what happens if it fails? still only get a click from the horn. no vibrations of the diaphragm.

 

If a resistor is bad that will normally put an open in the system causing the connection to be lost at that point. This could be the problem. Check the resistance at the resistor. The resistor should have painted bands on it to identify the ohm reading normally produced. google a resistor identification chart and test the ohmic value.