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1982 GN400 Horn

2317 Views 11 Replies 4 Participants Last post by  82SU
Trying to piece back a bike that I bought in Nevada where no safety inspection is necessary as opposed to here in Utah. So today's project is the horn. As many of you know this is a 6 volt system. When the horn is dissembled from the bike and a multi-meter is placed on both leads it has continuity. From there I moved to measuring the output of the wires that connect to those leads- 6.01V is what I got WITHOUT holding down the horn button, no difference when I do. This was just slightly under the battery voltage. When I connect it, the horn vibrates but does not make any noise, then when I push the horn button you can feel it but again no noise... When I took the horn off of the bike after the bike was running and all one of the leads on the horn was very hot, as well as the horn itself..

Any help here would be awesome, I know nothing really about electronics on these things so anything is appreciated.
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The short is not in the horn. I suspect it is in the mess in the headlight shell. The horn should not be getting voltage without the button being pushed. It could just be that the wrong wires are connected in the headlight. Whacking the horn is to dislodge any insects, dirt or rust which are preventing the diaphragm from vibrating as it should. Are you using the handle from a #3 Phillips? It should be pretty easy to identify the wires from the horn button and from the horn and see if they are properly connected in the headlight bucket. Check it against a wiring diagram, it is a pretty simple circuit.
Its simpler than that I believe- the horn should have power whenever the key is on and the battery is alive. The horn button switches the ground(negative). So you will read positive six volts at the horn even without pressing the button. But there should be no current flow(and heat buildup) unless the button is pushed. So the button is shorted to ground or the wiring is wrong or the wire is shorted to ground.
So look at the wiring diagram and trace out the wire going to the horn button.
Go here , download and print this diagram. Then figure it out, not much to it.
Once you get the circuit working, you can work on getting the horn to make noise.
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