The Stovebolt Site Forums The Shop Area The Electrical Bay ??? Bench testing a horn

Can someone please explain how I would go about bench testing a horn. It's probably a 6 volt horn.

Use a battery charger or battery and put the ground connection on the bracket or base of the horn, then touch the positive connection to the input wire or spade on the horn and it should sound

I don't know much about 6 volt but Ive heard that 12 volts will only make the horn louder ??? But Im not sure

good luck
Todd

I use a 12v transformer, converts 120AC to 12V, got it at Radio Shack years ago.

Take the horn and put a wire on the connection on the horn and ground the bracket to the neg post of a battery and run the wire to the pos post horn should sound. 12 volts won't hunt the horn for a test.

I field tested mine by hooking the positive terminal to the BATT terminal on the voltage regulator.

The negative terminal on the horn was already grounded to the manifold.

Just about made me crap my pants... It's loud on 6v.

I found my horn in the salvage yard, all it would do is click, so I took it apart, cleaned everything up and "adjusted" it and it works fine. 12 volt won't hurt it.

My point is, if you bench test it and it doesn't seem to work, don't throw it away until you tear it apart and play with it.

My six volt horns seemed to work on a battery charger but didn't work on a battery. This was because the points weren't working with steady DC but they would operate with pulsating DC. Cleaning the points and adjusting them corrected the problem. On 12V a good six volt horn is very loud.

if you clean the points how do you "sdjust them correctly"? Is there a certain guage thickness?? Mine wont' do nuthin!!

After cleaning the points you adjust them so the horn will vibrate. The working range is very small so either too loose or too tight and it woun't sing for you. If it doesn't draw any current, the points are too loose, too dirty or the coil is open. If it draws a lot of current but doesn't vibrate, they are too tight.

Most of the time all you need to do is polish the points an older wiser gentleman had told me to use paper like that of and old grocery sack (paper not plastic) at first don’t make any adjustments to the settings (screws, nuts) and just kind of clean or brush all the dirt n crud that might have built up and then using paper from the bag torn in strips about an inc wide and a few inches long hold open the points and insert the paper between them and let the pressure back on and drag the paper thru about four or five times to polish the points. He had said that if you use a file of emory cloth they can leave rough spots in the contact that will “weld together” if given the juice. I have done this method many times with great results. 52 & earlier horns have two terminals and one must be pos and the other to neg. 53 and later horns only have one terminal
Mike

I've checked them before...looong time ago but now its clear. Maybe check mine this week. I want it to be LOUD so folks can see,uh, HEAR me coming!! Thanks guys. Now, if I can just get my battery charger back from my son in law I won't even have to raise the hood.

An oldie but a goodie revived: with new a twist. In testing these, the term "points" is used in these earlier posts. In looking at my "clicking" and no other sound dual horns I'm not seeing these. Most likely because I don't know what I should be looking for. What do these points look like? I have a set of town and country horns I am preparing for eventual use on my '46 project.

Any help will be appreciated.

Make sure you are using the fully charged battery from your truck. I tried to test mine with an under-powered power supply and only got some clicking.
I then hooked it up to a fully charged battery while pointing it right at my head. Needless to say, it did not just click.
I SAID IT DID NOT JUST CLICK!

Ok, I'll try a different battery. I have used the spare one I keep on a charger when not in use for the tractor. It might be needed replacement.
Thanks.

Most likely the points are a set of contacts at the tip of a spring loaded moveable part (armature). Their purpose is to open a electric circuit through a coil when the armature is attracted to this coil and to close the circuit if the armature returns to its starting position.

Clicking is the sign for not opening the circuit, so the contacts are either welded together or wrong adjusted.[edit] or the armature can't move strong enough due to low power or mechanical failure [/edit] Adjustments affect the frequency, loudness and current draw of the horn. To keep an eye on current draw I suggest using a strong battery charger with an ammeter for bench testing.

If I remember correctly the adjustments are made at a nut and bolt at the armature (Cured my '54 3100s horn from clicking last year)

Just had a few minutes to test this today with a fully charged battery. Still no joy. Next step is to clean the points as was suggested in an earlier post. Thank you for the help in finding the points.