Voltage on horn wire, should it be there?

lw_miles · 02-19-2016, 08:36 AM

I'm trying to hook up airhorn on 2007 1600 so I'm using a relay. Never had issue with my stock horn. So when I press the horn button the air horn comes on and doesn't shut off. Called manufacture they sent me new relay stating they rarely see them go bad. Same issue call the guy back and he made some trouble shooting suggestions. I used ohm meter on switch it was fine. When I checked it for voltage I found is had almost 12v.. When I pushed the horn button it would jump to 12.5 volts.. Real head scratcher

. Is that voltage normal? If so I may have to install different horn button.

**BudMan** · 02-19-2016, 08:57 AM

If you haven't already read this thread and see if it helps.

http://vulcanbagger.com/forums/showthread.php?t=15936

lw_miles · 02-19-2016, 09:28 AM

Thanks Bud Man.... That's great write up. In looking at the simplified stock horn circuit it looks as though I may have a short somewhere as I get that voltage across my stock horn wires (wires completely disconnected from the horn) when the key is on and not touching the horn button at all. I took the horn switch apart yesterday (soooo glad I got it back together:). Expecting to see corrosion or something in there but nothing. I'll check the individual wires tomorrow to see if that one horn wire is indeed going to ground through the switch and perhaps I can use Scenario One in the link you provided but I'm afraid that's the wire with issue (short).

**cnc** · 02-19-2016, 10:14 AM

I am not able to check a scematics right now, but if I am not mistaken, the stock horn button completes the ground and if so there will always be voltage on the Pos lead when the key is on.

tonik · 02-19-2016, 10:51 AM

The poster above me is correct. The hot is always hot, the horn button completes the ground.

lw_miles · 02-19-2016, 01:51 PM

For my own sanity can someone please test voltage across the horn wires (NOT TO GROUND) and report if they see any voltage. From everything I learned they shouldn't. I get almost 12 volts WITHOUT HORN BUTTON BEING PRESSED. I'm not the original owner and there are some aftermarket items added and before I start tearing everything apart I just want to make sure what I'm seeing is not correct. Thanks

olefiredog · 02-19-2016, 03:42 PM

It sounds like you have a short to ground in the wire that comes from the horn button to the horn. If the button completes the ground side circuit to activate the horn, somewhere that wire is getting chassis ground fed to it. Or the horn button is stuck in a closed circuit position. That would give the horn a completed positive and negative circuit anytime the ignition is "on".

Check if you have 12V from the + horn wire to chassis ground with ignition on. You should have. Then try horn + wire to the other horn wire (-). If you have 12v there also one of the above seems to be the issue. Only time you should see voltage on second test is when the button is depressed.

How many terminals on the relay? you may wiring landed incorrectly especially since you said stock horn worked OK prior to this new installation.

Good Luck on the Gremlin search.

**BudMan** · 02-19-2016, 04:33 PM

Quote:

Originally Posted by olefiredog

It sounds like you have a short to ground in the wire that comes from the horn button to the horn. If the button completes the ground side circuit to activate the horn, somewhere that wire is getting chassis ground fed to it. Or the horn button is stuck in a closed circuit position. That would give the horn a completed positive and negative circuit anytime the ignition is "on".

Check if you have 12V from the + horn wire to chassis ground with ignition on. You should have. Then try horn + wire to the other horn wire (-). If you have 12v there also one of the above seems to be the issue. Only time you should see voltage on second test is when the button is depressed.

How many terminals on the relay? you may wiring landed incorrectly especially since you said stock horn worked OK prior to this new installation.

Good Luck on the Gremlin search.

My thoughts are similar to yours.
I don't understand how the stock horn was working. If reinstalled does it work properly?
If you are getting current passing thru the 2 stock horns wires without the horn button
depressed you have a problem and the stock horn would be on anytime the key is on.
Perhaps the button is stuck or a short on the ground side.

skiman · 02-19-2016, 05:49 PM

Take the hot lead of the stock horn and attach it to pin 86.
Attach the - wire of the stock horn to the chassis.
Run pin 87 to the + side of the air horn and ground the horn - to the chassis.
Attach pin 30 and 85 as shown.

**cnc** · 02-19-2016, 05:57 PM

Quote:

Originally Posted by BudMan

My thoughts are similar to yours.
I don't understand how the stock horn was working. If reinstalled does it work properly?
If you are getting current passing thru the 2 stock horns wires without the horn button
depressed you have a problem and the stock horn would be on anytime the key is on.
Perhaps the button is stuck or a short on the ground side.

Or perhaps there was no issue with the button till he took it apart and now it is stuck in the closed position.

lw_miles · 02-22-2016, 09:02 AM

Well after another few hours of troubleshooting without ripping apart the wiring harnesses there's an issue with the wire that goes to the horn button from the horn (other 12v side functioning as it should) and it's only issue when the key is on. I've checked the switch with ohm meter and it's functioning as it should. I appreciate all the input and what I'm going to do to resolve is KISS method of putting small kill switch on the handlebar to activate the horn.

olefiredog · 02-22-2016, 10:06 AM

Wonder if previous owner who added electrical accessories possibly tapped in the ground side wire from the button to the horn ? Then the wire would see a ground side circuit from another source possibly.

recumbentbob · 02-22-2016, 01:07 PM

Quote:

Originally Posted by lw_miles

Well after another few hours of troubleshooting without ripping apart the wiring harnesses there's an issue with the wire that goes to the horn button from the horn (other 12v side functioning as it should) and it's only issue when the key is on. I've checked the switch with ohm meter and it's functioning as it should. I appreciate all the input and what I'm going to do to resolve is KISS method of putting small kill switch on the handlebar to activate the horn.

That will work for a while.
I hope you don't fry the wiring harness

olefiredog · 02-22-2016, 01:28 PM

Smart money would run a new wire from the switch to the horn

scooter1600 · 02-22-2016, 06:42 PM

from what I can see here there is nothing wrong with the oem wiring.
the relay picks up a positive from the battery and powers the air horns
by completing the circuit with the horn button .you are powering the relay via the battery to power the horn and completing a negative circuit. releasing the horn button does nothing because the relay is still grounded thru the horn circuit causing it to make noise.thats why you use a relay give
the compressor more amps to operate.

02-19-2016, 08:36 AM	#1
lw_miles Jr. Member Join Date: Feb 2016 Posts: 4	Voltage on horn wire, should it be there? I'm trying to hook up airhorn on 2007 1600 so I'm using a relay. Never had issue with my stock horn. So when I press the horn button the air horn comes on and doesn't shut off. Called manufacture they sent me new relay stating they rarely see them go bad. Same issue call the guy back and he made some trouble shooting suggestions. I used ohm meter on switch it was fine. When I checked it for voltage I found is had almost 12v.. When I pushed the horn button it would jump to 12.5 volts.. Real head scratcher. Is that voltage normal? If so I may have to install different horn button. Login or Register to Remove Ads Last edited by lw_miles; 02-19-2016 at 08:43 AM.
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02-19-2016, 08:57 AM	#2
BudMan Join Date: May 2009 Location: Greenwood, Ark. Posts: 4,736	If you haven't already read this thread and see if it helps. http://vulcanbagger.com/forums/showthread.php?t=15936 __________________ Dave Jesse 2012 1700 Gray/Black Voyager 2006 1600 Nomad Green/Silver Sold VBA #1108 2010- Eureka Springs - Antlers - 2011- Maggie Valley - Antlers 2012- Margaritaville Ride - Van Buren - Antlers - 2013- Estes Park - Antlers 2014- Mountain View - Antlers - 2015- Eureka Springs - Antlers 2016- Salem - Antlers - 2017- Eureka Springs - Lake George - Antlers - 2018- Custer - Antlers
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02-19-2016, 10:14 AM	#4
cnc Join Date: May 2009 Location: Montreal QC Posts: 12,034	I am not able to check a scematics right now, but if I am not mistaken, the stock horn button completes the ground and if so there will always be voltage on the Pos lead when the key is on. __________________ Norm Ward 2008 blue / silver nomad kawanow / VBA #01136
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02-19-2016, 10:51 AM	#5
tonik Advanced Member Join Date: Dec 2009 Location: Cleveland Ohio Posts: 714	The poster above me is correct. The hot is always hot, the horn button completes the ground. Login or Register to Remove Ads
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02-19-2016, 03:42 PM	#7
olefiredog Member Join Date: Jul 2012 Location: Iowa Posts: 66	Horn It sounds like you have a short to ground in the wire that comes from the horn button to the horn. If the button completes the ground side circuit to activate the horn, somewhere that wire is getting chassis ground fed to it. Or the horn button is stuck in a closed circuit position. That would give the horn a completed positive and negative circuit anytime the ignition is "on". Check if you have 12V from the + horn wire to chassis ground with ignition on. You should have. Then try horn + wire to the other horn wire (-). If you have 12v there also one of the above seems to be the issue. Only time you should see voltage on second test is when the button is depressed. How many terminals on the relay? you may wiring landed incorrectly especially since you said stock horn worked OK prior to this new installation. Good Luck on the Gremlin search. __________________ Central Iowa Last edited by olefiredog; 02-19-2016 at 03:49 PM.
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02-19-2016, 09:28 AM	#3
lw_miles Jr. Member Join Date: Feb 2016 Posts: 4	Thanks Bud Man.... That's great write up. In looking at the simplified stock horn circuit it looks as though I may have a short somewhere as I get that voltage across my stock horn wires (wires completely disconnected from the horn) when the key is on and not touching the horn button at all. I took the horn switch apart yesterday (soooo glad I got it back together:). Expecting to see corrosion or something in there but nothing. I'll check the individual wires tomorrow to see if that one horn wire is indeed going to ground through the switch and perhaps I can use Scenario One in the link you provided but I'm afraid that's the wire with issue (short).
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02-19-2016, 01:51 PM	#6
lw_miles Jr. Member Join Date: Feb 2016 Posts: 4	For my own sanity can someone please test voltage across the horn wires (NOT TO GROUND) and report if they see any voltage. From everything I learned they shouldn't. I get almost 12 volts WITHOUT HORN BUTTON BEING PRESSED. I'm not the original owner and there are some aftermarket items added and before I start tearing everything apart I just want to make sure what I'm seeing is not correct. Thanks
	0

02-22-2016, 09:02 AM	#11
lw_miles Jr. Member Join Date: Feb 2016 Posts: 4	Well after another few hours of troubleshooting without ripping apart the wiring harnesses there's an issue with the wire that goes to the horn button from the horn (other 12v side functioning as it should) and it's only issue when the key is on. I've checked the switch with ohm meter and it's functioning as it should. I appreciate all the input and what I'm going to do to resolve is KISS method of putting small kill switch on the handlebar to activate the horn.
	0

02-22-2016, 10:06 AM	#12
olefiredog Member Join Date: Jul 2012 Location: Iowa Posts: 66	Wonder if previous owner who added electrical accessories possibly tapped in the ground side wire from the button to the horn ? Then the wire would see a ground side circuit from another source possibly. __________________ Central Iowa
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02-22-2016, 01:28 PM	#14
olefiredog Member Join Date: Jul 2012 Location: Iowa Posts: 66	Smart money would run a new wire from the switch to the horn __________________ Central Iowa
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02-22-2016, 06:42 PM	#15
scooter1600 Member Join Date: Sep 2015 Location: Sale Australia Posts: 157	from what I can see here there is nothing wrong with the oem wiring. the relay picks up a positive from the battery and powers the air horns by completing the circuit with the horn button .you are powering the relay via the battery to power the horn and completing a negative circuit. releasing the horn button does nothing because the relay is still grounded thru the horn circuit causing it to make noise.thats why you use a relay give the compressor more amps to operate. __________________ 2005 Nomad 1600 Cobra tru duals Dobec EJK 2.5/3.5/1.5/6/2.5/3.5 Cadmad / K&N + original intact Progresive 412HD / Front springs also Darkside rear tire 36psi 195/55/16 Towbar/ classic trailer Penrite HPR15 diesel oil Led lights front and back
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