Electric not strong enough to power horn

old_kaw wrote: Patton suggested several times hot wiring the horn to a known good battery. (solid advice!)

Take it off or just hook up power and ground with some alligator clip type jumper wires to a known good battery, and MAKE SURE that the horn actually works. Otherwise all of the "going over" this and that is a total waste.

If it was mentioned in any of the other numerous replies on "horn still won't beep" replies, I do apologize.

I thought it was the horn originally so I bought a brand new one and hooked it up and it did the same thing as the old one...that's why I haven't been thinking it was the horn. I'm going to find some wire to give it a try though, I don't have any handy here at the house. I'll keep the thread updated!

You may find out if you actually test both horns, that you are chasing the wrong ghost. I get alligator clip jumpers for ~$3.00 for a package of 10 at my local electronics supply house.

www.ebay.com/p/PC-Test-Lead-Jumper-Set-W...354?iid=141265800371

If your wiring is to weak for the current the horn need, i would install a relay mod.

We have been recommending hot wiring the horn to see if the battery is powerful enough to make the horn work.
It could be your original horn is bad and/or your battery is weak but some aftermarket horns just simply require too much power.

loudhvx wrote: We have been recommending hot wiring the horn to see if the battery is powerful enough to make the horn work.
It could be your original horn is bad and/or your battery is weak but some aftermarket horns just simply require too much power.

Very true, but a lot of other things were recommended in this thread as well...I just chose to try them first because I had the tools and it didn't involve going to the store and buying anything. It was easy enough to check the fuses and such, now I'll wire the horn to the battery! I just picked up some clips, I'll keep you guys posted.

Okay guys, I have an update.

I went to Advance Auto Parts on your recommendation and had the battery load tested...the cold cranking amps were half of what they were supposed to be, at around 80. The new batteries are supposed to be 160, so I went ahead and got a brand new one. The starter seems a little more eager to engage but there is still a slight delay sometimes. Also, the horn hasn't changed a bit...still completely weak.

So I bought some alligator clips and jumpered the battery directly to the horn. She beeps...loud, crisp and clear.

Maybe I missed a ground somewhere? Everything else on the bike works.

Legionnaire1856 wrote: Okay guys, I have an update.

I went to Advance Auto Parts on your recommendation and had the battery load tested...the cold cranking amps were half of what they were supposed to be, at around 80. The new batteries are supposed to be 160, so I went ahead and got a brand new one. The starter seems a little more eager to engage but there is still a slight delay sometimes. Also, the horn hasn't changed a bit...still completely weak.

So I bought some alligator clips and jumpered the battery directly to the horn. She beeps...loud, crisp and clear.

Maybe I missed a ground somewhere? Everything else on the bike works.

Pushing the horn button is supposed to provide a ground for current passing through the horn.

The horn button "ground" might be corroded internally whereby pushing the button is failing to produce a good ground. Which could impair horn performance even if full battery positive voltage is being provided to the horn as it's supposed to be whenever the ignition switch is "ON."

Could use a test wire to ground the horn with the ignition switched ON to see if the horn blows like its supposed to.

Could also test by using a hot wire to connect the horn positive terminal to the positive battery terminal.

I suspect that either the ground is unsatisfactory through the horn button when it's pressed. Or that the positive current from the battery is obstructed due to corrosion or faulty connections somewhere between the battery positive terminal and the horn's positive terminal. Or maybe both.

Good Fortune!

Bill gives good advice. (patton) He is right about the button grounding one side of the horn and the other wire should be B+ 12 VDC with key on. You can test the horn with a jumper, if y

You can test for 12 volts with a plain old fashioned 12v light bulb and jumper wire, test light or volt meter. I sometimes prefer the test light because it's brightness can also help to identify a flaky 12 volt feed. The horn, according to the service manual draws around 2 amps, and sometimes a corroded wire connection will not pull that much load, yet show B+ voltage when tested with a meter that has infinite input impedance.

It's great that you now KNOW that the battery is strong now, and KNOW that the horn is also good. I think prior to this info, my friends above were assuming that you had already tested the horn by it's self, and that the battery was indeed strong.

You will figure this out, now that you seem to be on the right track. Since the horn button normally grounds the circuit to the handlebars, perhaps you should try grounding the handlebars to chassis, in case there is a rubber bushing to isolate vibration on the risers. I am not sure about your bike, but some have a large wire terminal and wire grounding the risers at the mounting bolt that may be missing. Just a thought.

I prefer the AGM gel cell batteries, and they are relatively cheap (~$60.00 delivered) on fleabay.

I just fixed my horn issue, first I jumped the prongs on the horn with a battery and it worked , then I took apart the left hand control housing that the horn button is in.
there is a turn signal switch located over the over the horn button so I removed it by taking out 1 screw , that exposed the horn button.
then I sprayed a electric contact cleaner into the button housing and pressed it a bunch of times, after I let it dry a bit, I then sprayed Deoxit-5 into the button housing and pressed the button a bunch more times , then I switched the bike to on and hit the button.
It now works for the first time in over 30 years, I just never fixed it because I hate horns
If you try this make sure and spray/clean and operate the turn signal and hazard switch too.

Use one of those straw extensions for your sprays and aim in between the moving button part and the fixed button housing .
hope this helps

I also did similar last week but also scraped a bit of black paint off the handlebar where the switch housing clamps to the bar. Horn now sounds better than it has in years.
Horn button earths to the switch housing and switch housing earths to the handlebars and so on.

Yeah, my horn button only has 1 black/white too, probably the simplest circuit on the bike.
I didn't clean the ground though :blush: if it starts to fail I'll do it then, or not....

bluej58 wrote: Yeah, my horn button only has 1 black/white too, probably the simplest circuit on the bike.
I didn't clean the ground though :blush: if it starts to fail I'll do it then, or not....

Yep, a pretty simple circuit. We have safety inspections in MO that are required to get license plates. A working horn is required by state law. Also, if so equipped with turn signals, they are also required to work.

I just had my bike inspected last Friday, and as usual, it passed with flying colors. Since >all< MO motorcycle plates also expire every April (unlike cars with different months) .