Horn wiring

Rich'sToys

Well-known Member
Location
Southern MN
I am wanting to add a horn to one of my old trucks which doesn't have one. I had all the components except for the horn relay, which I picked up on Ebay. Of course, instead of simply labeling the terminals so you can understand them (power, ground, switch, etc.) they instead have numbers on them--30, 85, 86, 87. And no instructions included! After doing some online searching I came up with what I thought was the correct sequence--30 to the power source, 87 to the horn itself, 86 through the horn button and then to ground, and 85 also to ground.
Well, today I got everything hooked up except the horn button. I thought I should be able to test it by grounding the 86 (horn button) terminal, but when I tried it, nothing happened. Any ideas as to what I might have done wrong? Or am I missing something else here?
I ran out of time to trouble shoot it any further today, but plan to in the next couple days.
Also, how heavy of a fuse should this have? Everything so far is wired with 12 gauge wire. I thought I might use 14 to the horn button.
The horn itself is good. It blows when I hook it up direct.
Thanks in advance.
 
If you set your VOM to "continuity", you should be able to check out which combination of terminals sends power through.
 
Do you mean this little guy?? They are as common as dirt used in all
kinds of cars. The numbers are from EUROPE. If a single common horn a
10amp fuse is more than enough. Even two horns 10 is enough. I have
horns on every single lawn and garden tractor I own. Tells people and
the cats to get out of the way. So sad but the first set of horns are
on my IH 300U. Twin set of horns from a VW Karman Geha and was used to
shooo away the cows. Long long gone. This should show you how to wire
it up. Just ignore the air horn. Any questions just come on back.
a268166.jpg

a268167.jpg
 
If you are connecting it so the horn button provides the ground, you'll need to jumper 85 to 30.

Then when the horn button closes to ground, 86 will be the grounded, completing the circuit to pull in the relay contacts.
 
(quoted from post at 16:26:44 05/19/18) If you are connecting it so the horn button provides the ground, you'll need to jumper 85 to 30.

Then when the horn button closes to ground, 86 will be the grounded, completing the circuit to pull in the relay contacts.

Steve, that did it! I did a temporary hook up with some short wires and alligator clips. Did not have the horn button installed yet, but as soon as I grounded that terminal the horn blew just fine. I'll make the permanent hook ups next week.

Thanks for the help!
 
Why is a horn relay needed??? I have installed two horns on tractors and just ran a wire from the ignition switch to a push button switch and then a wire to the horn. That works for me.
Loren
 

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