I have an 89 sportster horn, it is grounded through the frame and there is only one lead on the horn from 86-90. I have tested the accy power and I get over 12v through the lead but no sound. any thoughts? this has been bothering me forever. I have a replacement horn that is suppose to work but it has two leads. I can hook up either lead and it gets power as well. I have even tried piggy backing the two leads and it still gets power but no sound. ????? puzzled

 

Check it for mud wasp nests. Sounds stupid but i had a horn on my boat that acted the same way. Flushed the nest out with a hose and it worked fine : )

 

youre sure its not a fuse? if i am remembering correctly that fuse also does the tail light, but i could be wrong.

 

One lead should be power and the other ground, they do it that way on aftermarket ones incase they are mounted on plastic.

 

There are no mud wasps, it is clean. The tail light works fine but it might be rewired. Like I said, if i put the volometer to the cable that gives it power and ground it on the frame where the horn is bolted and press the horn button I get 12v+ of juice running to the voltometer. But if I hook up the horn nothing comes out on either the stock one or the replacement. if I pull the plug back a bit and keep the voltometer on it the power still flows but no horn sound. And no I am not def. lol

 

Step #1:
Take the horn and connect it directly to the battery and see if it works or not.

If it does, you have a wiring/switch problem.
If not, throw the horn away.

 

The single lead is grounded through the body of the horn back to the frame mount to complete the circuit. The double lead uses the second lead to go back to ground or if wired differently to a switch to complete the circuit and blow the horn. If you look at the body of the horn,there should be a small screw that is used to tweak the horn so when it blows the diaphragm vibrates and makes and breaks the connection. If you tweak that screw it may start to work if it is not trashed. It only takes a small movement to tweak it so remember where it was before you started. Sometimes a sharp rap on the body of the horn will start it working, corrosion inside is the culprit here.

You can use a connection to the battery directly to test it out. One from the POS to the single connection on the horn and a jumper from the horn body to the NEG of the battery providing the horn only has one wire terminal. If it has two connections, then the POS and NEG are needed to be connected to the battery to blow the horn.

 

Just wanted to update and let you know, @ Peppi that did the trick for sure. One dead horn and then I had the replacement which once i grounded it back to the frame works perfectly.

 

It doesn't matter, no one can hear it anyway. Just my worth. Horns on motorcycles are useless.

 

I thought so, too, until earlier this week. Was taking a trip and a couple people were jaywalking while I was doing 40-45MPH down the road. They seemed not to notice (not sure how, my bike isn't exactly quiet), but laying on the horn got them to move pretty damn quick.