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1982 GN400 Horn

2316 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.
Kenessex thank you for picking up on my clues and symptoms. I have taken apart the left switch assembly a couple times and everything looks really clean inside, but the colors of the wires dont match up with the wiring diagram, (no spiderwebs or anything and wires look healthy) But when it gets to the headlight cavity everything is a mess with the wiring in there. I have adjusted the screw on the back of the horn as well and like i said it only does a slight vibration...UPDATE... when I turn the key off right before it is in the OFF position a little tiny beep comes out of the horn, but if the bike was running you wouldnt be able to hear it.

Do you think the short is in the horn and by whacking the horn itll work?
Sorry for the slow response guys, I've been elk hunting. I think that I have got it fixed. I tore of all the tape in the headlight cowl and all the way back to the battery to make sure there weren't any bad covered up connections. There was a questionable one in the headlight that I fixed but I dont think it was giving me any issues. I ended up banging the horn with a wrench because I didnt have that driver handy. After it still would just buzz I started messing with the screw on the back of the horn and ended up finding a spot where it would work when the button was hit (I had also taken off the blinker/horn/light switch to check connections) So i got it fixed to where I wanted it when I tested it and put it back together. When I got all the wires taped up and the switched mounted back together now instead of a constant buzzing when I turned the key on it was the actual horn. I got it to stop and then when I would hit the blinkers or lights it would start again. After this hint, I started looking and could actually see it arcing from the control switch to the handle bars. After I electrical taped the handle bars underneath the switch and remounted it, the short had stopped! Everything seems to work fine now, thanks guys! Im not sure if this was how I was supposed to fix it or not but it works.
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