Horn + general electrical questions

[exzachtly1]

First some background - my OEM horn was NOT working before this. I decided to replace it with a new horn and sort out any potential issues with the circuit later.

Well, I have issues with the circuit as I do not seem to be getting any power at the horn terminals. I have a new horn (Fiamm freeway blaster low tone) and was hoping to run it without installing a relay. My understanding is that the amperage of a single Fiamm is not high enough to require it... though I may be interested in adding one later to improve the horn and maybe add a second tone.

So far I have read through this article and I think I understand how the horn circuit works, but I am not confident with electrical stuff and am having trouble determining if I am doing the tests right. I was trying to use my multimeter. It's this one:

Had it set to DCV, with the plugs in the correct terminals. What I found was that I could not get a reading at the hot (green) wire at all, either when grounding directly or trying to use the horn button.

I -think- I also confirmed this when I hooked up the new horn and tested it with no result. But I'm not sure if I had the horn hooked up right...

So now a few questions:

1. What is the right way to hook up the horn? Both existing green wires into the 2 terminals, with the existing ground wire (that goes to the horn switch) connected via the mounting bolt (same as the old horn)?
2. How do I test the fuses properly with the multimeter? I tried it with the power disconnected, using the ohm setting and touching the leads to both ends of each fuse, and they all read 0 - does that mean they are all good?
3. If the fuses are all good, then I have to assume something is junked somewhere along the line from the fuse box to the horn. Does this mean I need to trace the whole harness? Any advice here?
4. I discovered that I have a wire connected to my fuse box that is very loose. It came disconnected when I pulled the fuse box out. I tried to tighten the connector and managed to send some sparks flying... I'm guessing I need to disconnect the battery before I go messing with this trying to tighten it up? There's no slack to work with so it's a pain... might need to add some wire. Any suggestions? When this wire is disconnected nothing works... no lights or anything. Freaked me out at first cause I didn't know it had come undone

 

[chuck hahn]

How about on each side of the horn button mechanisms themselves? Maybe the contacts are jacked?? I fhtere is power TO it..but not out...then I would see about rebuilding the button.

 

[exzachtly1]

How about on each side of the horn button mechanisms themselves? Maybe the contacts are jacked?? I fhtere is power TO it..but not out...then I would see about rebuilding the button.

Hmm maybe, but what about the test of connecting directly to the negative battery terminal and to the hot horn wire (test 2 in the article I linked)... I don't think that worked unless I was doing it wrong. That would bypass the button and give me a reading, right?

Here's how I did it:
- DCV setting
- Black lead to neg battery terminal
- Red lead to hot horn wire
- turn on key

I assume that if it was working I'd see ~12v at the meter? Did I do it wrong?

 

[chuck hahn]

Have you went directly to the battery with 2 wires to the horns neg and pos terminals to see if it works?

if so, put the black lead to the neg on the battery. Next turn on the key and see if there is voltage on the feed side to the horn button with the red probe..if so, then press the horn button and hold it in and see if there is voltage on the downstream side of the button..if not, then the button is in need of repair.

EDXIT..remember that some bikes used the handle bars as direct grounds for the switch oxes. Make a jumper wire from the switch housing to something like a handle bar cap bolt or other frame ground point.

 

[Steve]

Do the new horns have one terminal or two? If they have two terminals (+ and -), you are in business.
If they only have one terminal (and use the case for a ground), sorry, but you WILL have to use a relay.

The way the stock horn circuit works:
1. Power comes from the second fuse from the end of the block, which also powers your brake lights and your turn signals. If they work, your horn should work.
2. The green wire at the horn should come ON when you turn on the key. If it doesn't, you will need to find where you are losing power between the fuse and the horn.
3. Power goes in one terminal of the horn and out the other terminal, toward the switch.
4. When the switch is pushed, the circuit is completed to ground, whether the ground is through the bars or a separate wire.

If your new horn has two terminals, just hook them up the same as the stock horn.

If your new horn has just one terminal, install a relay instead of the stock horn. Connect the two horn wires to terminals 85 and 86 (doesn't matter which wire goes to which terminal). Connect relay #30 to a fused wire from the battery. Connect relay #87 to your new horn. Make sure the horn is properly grounded.

.

 

[exzachtly1]

Have you went directly to the battery with 2 wires to the horns neg and pos terminals to see if it works?

if so, put the black lead to the neg on the battery. Next turn on the key and see if there is voltage on the feed side to the horn button with the red probe..if so, then press the horn button and hold it in and see if there is voltage on the downstream side of the button..if not, then the button is in need of repair.

EDXIT..remember that some bikes used the handle bars as direct grounds for the switch oxes. Make a jumper wire from the switch housing to something like a handle bar cap bolt or other frame ground point.

I have not tested the horn directly. Gotta find some wire around to do this. Will probably take a look and do these tests tomorrow or later this weekend.
Does it sound like the test I did was correct? DCV setting on the multimeter, and should I expect to see ~12v when it is "ON"?

Do the new horns have one terminal or two? If they have two terminals (+ and -), you are in business.
If they only have one terminal (and use the case for a ground), sorry, but you WILL have to use a relay.

New horn has 2 terminals. It comes with a jumper wire to support single-wire installs too, but it appears that it should be able to install the same as the old one like you said.

 

[exzachtly1]

So the loose wire I am dealing with on the fuse box - is this the main power wire that goes directly to the positive battery terminal?

If so, how can I fix it? Is the wire 16 gauge or 14 gauge, and can I just cut off and replace the old female connector with a new one? I'll probably have to extend the wire if I do that as it is very short with almost no slack. OR should I just try to clamp it down a bit to get a tighter fit?

 

[exzachtly1]

OK, still pretty confused but hopefully getting closer.

I took apart the switch assembly and tested the contact where you see the green wire here. Got no reading while switching the button on / off. Does that mean the wire is bad somewhere? Shouldn't this wire have voltage without pushing the switch and with the key ON?

Here is the wiring diagram. Should I be testing the green/orange wire too??

Any ideas? More places to test??

 

[exzachtly1]

Yeah, I was checking things wrong. I had the horn unhooked so the green wire to the switch was of course getting no power

Checked the OTHER wire - G/O wire (the one coming from the fuse box) - and getting a little over 11 volts. With the new horn hooked up, I am seeing the same at the G wire terminal and at the G -> horn button connection. When I pushed the horn button I actually heard a very feeble popping sound like it was trying to go off. So it's definitely that switch.

Before I take it apart, do I need to be concerned about little pieces flying everywhere?? It seems to be held in place by a zip tie where the wire runs into the housing, and a little tab at the bottom - do I just cut that tie and release the tab to pull the inner assembly out?

Once it's out - is simple green the best for cleaning the parts? I don't have anything on hand since this is really the first time I've ever done this kind of work.

 

[Steve]

Checked the OTHER wire - G/O wire (the one coming from the fuse box) - and getting a little over 11 volts.

Under those same conditions, what is the voltage across the battery terminals?
If it is also 11 volts, you have a weak battery.


.

 

[exzachtly1]

Under those same conditions, what is the voltage across the battery terminals?
If it is also 11 volts, you have a weak battery.


.

I was getting around 12.5 to 12.6 at the battery if I recall correctly. I'm going to do more tests tomorrow (stator tests) and maybe pull the battery to have it tested. I don't know the history of it and have had the same one since buying the bike last year. We will see... The horn connectors are in bad shape and I plan to replace them.

 

[exzachtly1]

Well I got the switch apart and attempted to clean it. It didn't look too bad really. However I am still only getting around 2.4 volts down stream when I push the button. This is measuring from right where the outgoing wire from the button connects. Any suggestions? Feel like I'm getting close but not sure what else to do to get it cleaner.

Here's a pic

That wire to the upper right of the green connector... it's got some gunk but doesn't look too bad to me.

 

[exzachtly1]

I cleaned that contact up, replaced all of the connections at the horn including the ring connector for the ground wire, and got the horn button pieces squeaky clean and ensured that they are making good contact. STILL no luck. I'm feeling like the switch is probably in good shape and the problem is somewhere else... but where??

I'm confused now where I should be looking. Every time I push the horn button I get a massive drop in voltage... ~3 volts at the ground connection to the button itself, the same at the G/O wire at the horn, and about 7 or 8 volts at the G wire (I might have those last 2 backwards but I think it's right).

I looked through the whole harness with the tank off, the connections all seem fine. Had a little trouble tracing the ground wire, but I think I was able to trace it back to the neg terminal on the battery.

Also confirmed that the horn is fine by connecting straight to battery with some wire. WOW it's loud!

Last thing, and this is a mystery to me... there was this little part inside the switch housing. It looks like a tiny washer but I can't figure out where it goes. Fiche doesn't show an exploded view of the switch assembly so it's hard to say. Could this have something to do with the button??? Anyone have some light to shed on this?

Please help! I'm totally out of ideas and things to check.

 

[posplayr]

I cleaned that contact up, replaced all of the connections at the horn including the ring connector for the ground wire, and got the horn button pieces squeaky clean and ensured that they are making good contact. STILL no luck. I'm feeling like the switch is probably in good shape and the problem is somewhere else... but where??

I'm confused now where I should be looking. Every time I push the horn button I get a massive drop in voltage... ~3 volts at the ground connection to the button itself, the same at the G/O wire at the horn, and about 7 or 8 volts at the G wire (I might have those last 2 backwards but I think it's right).

I looked through the whole harness with the tank off, the connections all seem fine. Had a little trouble tracing the ground wire, but I think I was able to trace it back to the neg terminal on the battery.

Also confirmed that the horn is fine by connecting straight to battery with some wire. WOW it's loud!

Last thing, and this is a mystery to me... there was this little part inside the switch housing. It looks like a tiny washer but I can't figure out where it goes. Fiche doesn't show an exploded view of the switch assembly so it's hard to say. Could this have something to do with the button??? Anyone have some light to shed on this?

Please help! I'm totally out of ideas and things to check.

When you say "cleaned up" , what did you use? Contact cleaner or something else like navel jelly to clean corrosion?

Did you test it using an ohm meter?

 

[exzachtly1]

When you say "cleaned up" , what did you use? Contact cleaner or something else like navel jelly to clean corrosion?

Did you test it using an ohm meter?

Honestly, it was barely dirty or corroded at all to begin with. I cleaned up the button contacts (just a bit of corrosion) with some steel wool and sprayed the gunk off with wd-40. I have been testing the DC voltage with my multimeter; what should I check with the ohm meter?

I understand that wd-40 might not be the best for electrical stuff, so if I need to take the thing back apart I will. I just didn't have any other cleaners on hand.

 

[posplayr]

Honestly, it was barely dirty or corroded at all to begin with. I cleaned up the button contacts (just a bit of corrosion) with some steel wool and sprayed the gunk off with wd-40. I have been testing the DC voltage with my multimeter; what should I check with the ohm meter?

I understand that wd-40 might not be the best for electrical stuff, so if I need to take the thing back apart I will. I just didn't have any other cleaners on hand.

Do you have any Naval jelly? use that to clean the contacts and crimps. There is usually corrosion inside of the crimps. Of course after you do this the copper is bare and it will corrode again. That is why Detox-it is recommended it leaves a weather proofing. I usually just flow some solder into the crimps of critical connections.

To use the ohm meter, disconnect the battery ground and measure the resistance from the battery (+) post to the O and O/W outputs

 

[exzachtly1]

Do you have any Naval jelly? use that to clean the contacts and crimps. There is usually corrosion inside of the crimps. Of course after you do this the copper is bare and it will corrode again. That is why Detox-it is recommended it leaves a weather proofing. I usually just flow some solder into the crimps of critical connections.

To use the ohm meter, disconnect the battery ground and measure the resistance from the battery (+) post to the O and O/W outputs

I should clarify... I cleaned only one connection inside the switch, the connection that I understand to be the one that goes from the switch the ground (pictured a couple of posts back - the one I mentioned as having some gunk). Are you saying I should go through and clean all of the connections along the bike?

For the ground measurement, I'm not sure which O and O/W outputs you mean. Are these near the battery? Is the point of this to test the main ground from the battery?

 

[posplayr]

I should clarify... I cleaned only one connection inside the switch, the connection that I understand to be the one that goes from the switch the ground (pictured a couple of posts back - the one I mentioned as having some gunk). Are you saying I should go through and clean all of the connections along the bike?

I have not been following this thread in it's entirety but was just giving some general recommendations. I know Steve was helping but you still seem stuck.

I drew a simple diagram of the circuit with color codes. I was mistaken about the O/W; this is an O/G circuit coming from the fuse box. See the attached figure. I think Steve described this before but if it was not clear the horn is operated with what is called "low side" control. That means the horn will not operate until current flow through it. The high side (+) is always connected (albeit switched through the ignition switch), and the horn is operated by grounding the green or low side of the horn. This operates essentially just like the solenoid.

I would go about this basically as follows.

1. make sure that you have 12V at the horn O/G (if not go back and start at the fuse box O/G and go to the Horn O/G )
   
2. measure the voltage at the green side it should go from 12v (with horn off) to 0V (with horn on). (If not check the horn button for functionality using the ohm meter)
   
3. Disconnect battery (-) and verify the horn button is OL (when button normal), 0 ohms (when button depressed).

 

[exzachtly1]

I have not been following this thread in it's entirety but was just giving some general recommendations. I know Steve was helping but you still seem stuck.

I drew a simple diagram of the circuit with color codes. I was mistaken about the O/W; this is an O/G circuit coming from the fuse box. See the attached figure. I think Steve described this before but if it was not clear the horn is operated with what is called "low side" control. That means the horn will not operate until current flow through it. The high side (+) is always connected (albeit switched through the ignition switch), and the horn is operated by grounding the green or low side of the horn. This operates essentially just like the solenoid.

I would go about this basically as follows.

1. make sure that you have 12V at the horn O/G (if not go back and start at the fuse box O/G and go to the Horn O/G )
2. measure the voltage at the green side it should go from 12v (with horn off) to 0V (with horn on). (If not check the horn button for functionality using the ohm meter)
3. Disconnect battery (-) and verify the horn button is OL (when button normal), 0 ohms (when button depressed).

Thanks for the info, I just did the tests you indicated and here are the results.

BATTERY:
12.5v with key off
11v key on

CONNECTIONS AT HORN:
KEY ON:
~10v at G and G/O wires

KEY ON, BUTTON PRESSED:
3.2v @ G wire
7.2v @ G/O wire

BUTTON (with neg battery terminal disconnected):
Normal: 1.2 Ohm
Pressed: 0 Ohm

Obviously some bad results, but I'm not sure what exactly they mean or where I should look to next.
I want to make sure I did the last test correctly, too - here is a picture to illustrate where I tested:

Is that correct? It's a little hard to see the black terminal as it is under that other wire. But it looked right to me based on what I saw when I had the switch completely apart.

Any ideas??

 

[posplayr]

Thanks for the info, I just did the tests you indicated and here are the results.

BATTERY:
12.5v with key off
11v key on

CONNECTIONS AT HORN:
KEY ON:
~10v at G and G/O wires

KEY ON, BUTTON PRESSED:
3.2v @ G wire
7.2v @ G/O wire

BUTTON (with neg battery terminal disconnected):
Normal: 1.2 Ohm
Pressed: 0 Ohm

Obviously some bad results, but I'm not sure what exactly they mean or where I should look to next.
I want to make sure I did the last test correctly, too - here is a picture to illustrate where I tested:

Is that correct? It's a little hard to see the black terminal as it is under that other wire. But it looked right to me based on what I saw when I had the switch completely apart.

Any ideas??

first as you already know the battery is in poor shape, but it might be even worse that you think without the horn, it is already dropping to 10.0V which is about 1.2V lower than it should (12.2-12.4v with key on is a healthy battery)

now there two measurements are interesting because if your are on the high side (of the horn), then you should be at the battery voltage and if you are on the low side you should be at ground (i.e. 0V). Anything else and there is resistance in the current path other than the horn.

With the 7.2V on the G/O see how much the battery is at; is it also at 7.2V or maybe a little higher? If he battery is still at 10V you have a huge resistance somewhere between the battery through to the ignition switch and fuse box back to the horn.

The 3.2V on the G is saying that your horn button is dirty and needs cleaning.