The Stovebolt Site Forums The Shop Area The Electrical Bay Horn Testing

When I opened the horn on my 52 1/2 ton Chevy to start restoring it, I noticed the capacitor and the coil were burnt out. I have found another horn at a salvage yard. Can anyone tell me the easiest way to test the horn I found to see if it works? I do not have the truck available to test it in.

Hook it up to a car battery and see if it works.

Before doing that in you have a continuity tester hook that up first and see if you have continuity, If yes then grab your ear plugs and try in on the battery, if no continuity then it won't work. Good luck

Thanks for the replies. It was no good.

If no continuity , before tossing away a perfectly good original horn , try filing the points ~ I save 99 % of the old ones I find that way .

99% ha ???
If it is a 6 volt horn you need to run 6 volts through the horn USING THE ORIGINAL HORN RELAY.
I dont think VW nate knows anything about the original Delco relays. Volkswagen Nate, you can file those horn points all ya want but if ya dont use the correct horn relay before firing them up again , those points will be nothing more than a cheap spot welder.

Normally the horns work best, when one you are under the hood checking the oil, and the wife hits the horn button to attract attention of a friend.... :rolleyes: But cleaning the points inside and setting the set screw on the outside also helps..

Well MT , I'm sure you know a relay is not going to do anything to the horn , it is to protect the
contacts in the horn button and contact ring on the column mast jacket .

Running a 6 volt horn on 12 volts is another whole deal , again relays have nothing to do with it .

Of course I always use horn relays even when not originally fitted but this thread was about salvaging old horns , not preference in wiring .

I wonder why you;re always so negative when supposedly you claim to know everything about old trucks ?

Sucess comes in _cans_ not in cannots .

Have a good weekend all , I'm off to work on my truck and D's '54 sedan .

Volkswagen Nate. We finally meet again. The reason I am so confrontational with you is because you answered a coolant/radiator post of mine a year & a 1/2 ago saying I was full of B.S. [ because you talked to some " chemists" about it]. Talk about negative!!
Then you disappeared for a year. Now you are back like nothing happened.
Let me refresh YOUR " know it all mind " Nate.
I posted a reply to a coolant question with....
" Dont use distilled water. Distilled water has a different specific gravity than tap water & distilled water & coolant will break down faster over time & turn into a corrosive mixture that will cavitate the coolant system . Use tap water & ad 3 tablespoons of baking soda along with the coolant [ this neutralizes any acid & the coolant will last much longer ].
I learned this trick from an old guy [who is now passed away & this guy worked at the Harrison radiator plant in the 40's & 50's ".
I have used this technique on my 51 1/2 ton & have never had a problem [ in 25 years ], this truck still has the original radiator it came from the factory with.
So Nate, enlighten us on your antique truck coolant knowledge [ & dont apply everything you know about late model fleet cars to old trucks that are 50 years old ].

Okay, MT and VW, how the he!! does this little personal hate-fest of yours have ANYTHING to do with the question asked about horn testing??? If you don't have anything to say on the topic, shut up. This kind of personal nastiness has no place on one of the techinical forums.

Just my opinion.

"Well MT , I'm sure you know a relay is not going to do anything to the horn , it is to protect the
contacts in the horn button and contact ring on the column mast jacket ."

Volkswagen Nate, why would a HOT horn relay protect a horn button when the horn itself is always hooked up hot to a power source. The only thing the horn button does is to ground the system when you press the horn button making it beep. So why would a relay protect a ground wire ??

Nate I now understand why you dont know anything about vintage water cooled American trucks.....
Volkswagens are air cooled !!!. Maybe you should move to this sight Nate..... http://www.volkswagenbkk.de/

Not to get into this problem of yours, but the relay doesn't protect the horn button or ground wires. It protects the truck and you from having live (+) wires running along the steering shaft. It's just a safety issue. Horns pull alot of current and its easyer to run a relay and not have the heavy wires in the column. If the wires get rubbed into, all that happens is the horn honks till you unplug it. If the (+) wire was to rub into, you would have one heck of a spark show and a lot of burnt wires.

The horn will work with or without a relay. You can wire them dirrect to the battery, and it wouldn't work any different if it was wired though the relay!

Its the same reason there is a high speed relay on your heater blower motor. Its easy on the switch, and cheaper to run smaller wires. Joe

Gotcha on the horn Joe, but none of my original trucks have a relay for the heater. My orig. trucks heaters are wired from the ignition switch to the 3 way motor switch & then directly to the heater blower motor. What is the Delco part # on this heater relay switch ? & where is it mounted??

[QUOTE]Originally posted by GMCpanel:
[QB]Okay, MT and VW, how the he!! does this little personal hate-fest of yours have ANYTHING to do with the question asked about horn testing??? If you don't have anything to say on the topic, shut up. This kind of personal nastiness has no place on one of the techinical forums.

I see nothing about the subject in this post by GMC panel except nastiness.
Not a good idea to stick your hand in between two fighting dogs or ya may get it bit off.

Still waiting on an answer from VW nate on the coolant question & more importantly from Joe H on the location of this supposed heater relay .

Sorry about the delay, the older units may not have a relay on the heater motors. It was something they added later on. Most new trucks and cars now have them. Joe

For those of you who are interested in learning more about relays used with horns and other things, check out this link.

Old Burb Club info on Bosch Relays - too bad this site is inactive, but it still exists

Here is good example of the relay in use:

Old Burb Page again - good electrical info on this site

Yes, I know this particular relay has little to do with a stock Stovebolt relay but the general principle is the same.

Is a horn-relay needed in order to bench test a stock horn?. I think not; but, I do not want to fry a pair of original hi/low horns that stopped working when I painted them. I need to easily bench-test these horns - any comments?

Tim

Tim , I just hook the horn right across the battery , get a blast if it works , or not , if not .
Good links on the Bosch relay info , thanks.

I agree for testing the horns a relay is not needed, the relay is only used to reverse the polarity so to speek. the horn is grounded (-)through the case, the terminal of the horn must be connected to the Non grounded (+) side of the battery to work. The horn button only has a single wire going up the colume, so it can only ground out that wire to the colume, using the relay one side of the coil goes to the positive(+) the other terminal to the wire from the mast, making one circuit, the wire from the horn(s) goes to the third ternimal of the relay to get to the positive of the battery.

Sorry about the late reply MT , I don't have the free acess to a computer all the time .

You're right about the baking soda , it wasn't in your old coolant post long ago , I still say plain water isn't good as most tap water is
' hard ' and creates deposits . I use distiled water with coolant .

I don't work on late model stuff BTW , only vintage and I don't even own a modern car / truck .

The relay does indeed protect the horn button contacts as the horn pulls much more amperage than the relay does , that is the _entire_ point
of relays , they switch the operating current instead of the horn button or switch thereby protecting it from wear/burnout .

Just testing horns is find but as I said : I get
" dead " horns for free and rarely cannot fix one
by carefully filing the points then correctly adjusting them .

_ALL_ of my posts here have directly addressed the questions asked .

Sorry we got off on the wrong foot so long ago , please feel free to bury the hatchet , just not in my back or truck , 'K ? .

I don't know sh*t , I think that is _OBVIOUS_ .

I dunno why they don't use relays in heater blower circuts , it sounds like a good idea to me

I can think of one reason for not having a relay in the heater blower circuit. The switch (at least the one I have) has a resistor on it, with a wire at each end, and one in the middle, providing for high and low speeds. Run that through a relay, and you would only have one speed.

Nate , I think ya do really know alot about the automotive troubleshooting game, but when ya step up & say someone is full of crap after they have posted a reply to a technical question ya gotta be there to back up the comment & you have been gone for over a year. So I only picked up where we left off.

MT , that Sounds fair to me .

I am sure we have provided much amusment to the rest of the board =:-) .

GMC , you're correct about the heater switch , I was thinking of 60's vintgae ones where GM out the resistor coils in the defroster vents for cooling - a good idea I guess ? .