2005 WR450 Dual Sport

So I plated my WR450, I installed a Vapor Speedo, a brake light and a horn.

My problem is that I hooked the vapor speedo up to the battery, as well as the horn and the tailight all seperately to the positive terminal. Everything was working fine, speedo was working and the horn and the taillight. I figured I might clean up the mess, so I soldered the vapor positive wire to the horn positive wire and the horn stopped working! I cut the wire and made them seperate again both going to the positive terminal. Still horn is unable to work.

So I hooked the battery charger up to the horn only and it will work just fine, but when I have it on the the actual battery terminal it wont work.

Any suggestions?

When you hooked the charger up was it + to the same wire as it would be hooked up to the battery and it would operate w/the switch/button? or did you hook it up to the horn directly?

Does the horn have its own feed from the positive to the unit? Horns draw a lot of current, if it's an undersized or shared feed it will not work.

I have a Vapor and Tusk kit on mine without issue so it will work.


When I hooked up the horn to the charger I just hooked the positive alligator clip to the, horn positive wire, as if it was hooked up to the battery...Then when I pressed the horn button on the bars, it worked just fine...

So in short, it wasnt hooked up directly to the horn...


I believe the wiring goes as follows...horn button on the bars has one wire going to the one post on the horn, the other post on the horn, i wired to go back to the positive term on the battery...

The horn is a tusk 12v horn, I wanna say it draws 2.5 amps?

I have a the vapor, tailight, and horn all ground to the same bolt...As well as each one going to the positive terminal on the battery...

Actually come to think of it, the last thing I installed was the tail light, so do u think that the taillight plus the horn might be drawing too much from the batttery?

Doesn't sound right. Double check the directions because I think the button sends the +12, not provides the ground. I might be backwards so check the instructions because it's been a few years.....

Someone correct me if I'm wrong.

The button grounds the horn.

The button grounds the horn.

Ok, thanks for correcting me then, could have sworn it was not setup that way.

Wish I had my 04 right in front of me because it was easy to setup and following the directions went on without issue years ago when I did it. The one thing mine has issues with right now is I read on someone's post to pull power off the unused taillight circuit so you don't run the risk of leaving it on and since then the horn doesn't work well because the wiring doesn't provide enough current to clearly sound the horn.

I've not cared enough to redo things to bypass the on/off switch and still provide enough current to run the horn correctly, but I do know that when I originally hooked everything up just like the directions said it worked perfect. May want to start you +12 and ground feed again on each item individually and make sure you can isolate what's not working. Meter would help a ton here.

The horn alone can be hooked up to the battery. However, you should splice power from the bike to hook up the tail light and the speedo. That is the best way to do it.

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