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1982 GN400 Horn

2319 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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You guys seem to have missed the little tidbit of there is a constant 6V to the horn even when the horn button is not pressed. The other little clue he presented is that the horn and wires are hot when he is running the bike. The horn and wires are not designed to have constant voltage with no work being done, i.e. the horn not vibrating. So there is yet another problem, as in either the horn button is stuffed or there is a short in the system. Either way, take the left switch assembly apart and look for the wiring problem. Besides the adjuster screw on the back of the horn, quite often there is a build up of rust and insects in the horn. Try giving it a few whacks with a screwdriver handle while it is activated and see if it starts squawking. I generally use a #3 phillips from Snap-on with the black triangular handle. It has just a little more heft than the #2.
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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.
I still think it needs whacking with a #3 phillips handle. Practically everything can benefit from that. I know it works on sticking floats and starter solenoids.
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