Firstly, I am not mechanically/electrically minded so here is my question.

 

I have an air-horn that now no longer works. It connects to the 2 original HD plugs and has a third wire that has an in-line fuse that connects to the positive terminal of the battery. It all goes through a relay that was attached to the horn at pruchase.

 

When activating the horn now, all I hear is a clicking which I guess is coming from the relay. I have checked the in-line fuse and it does not appear to have any damage to it. No broken wire inside it and no burn marks.

It was working yesterday morning before a long ride and later in the afternoon when I activated the horn, it emitted a small sound before cutting out......and hasn't worked since.

 

Anyone have any ideas of what it might be? Does the clicking sound indicate the relay is working and it's my horn compressor that is now fucked?

 

Hesh

How would I test with a multimeter? Not electrically minded so I would put what on where? I can grab a mulit-meter from work and test it.

 

Hesh

Try connecting directly to the battery from the horn. 2 wires.. If the horn works then the relay is stuffed. Using a mutlimeter will give the same result as well. Connect to the horn then activate the horn button and you should get a reading of volts being applied to the horn. No volts = stuffed relay. Replace and rewire and should be good to go.

 Ok, I shall grab a multimeter from work. Horn should still be under warranty but as my luck would go, I bought it from overseas.

So.....if when I place the meter on the relay plugs and I get a reading of around 12V when I press the horn, then that would mean that the relay is working and maybe the horn is fucked?

 

badcooky, yes that is a skull on my tank. I have the matching one on the other side which is the fuel cap, except it doesn't have the LEDs for the fuel gauge.

Not sure about the acronym though, what do you think it means?

 

Hesh

If you have a test globe (in this case, one of those $3 Super crap ones is good enough) , disconnect the horn and shove one end of the test light into where the horn red wire was, and the other end of the test light on to the battey -ve. Hit the horn button and the light should glow noce and bright. If not, the relay is cactus ( more likely the fuse has fatiqued or broken even though it looks good.) Multimeters are good, but for this sort of thing the test light is better.
Tech stuff- if a wire / relay contact is high resistance a multimeter will show 12 volts and so you will assume the circuit is OK. But a multimter only needs .0001 amps or less to make a voltage measurement. A high resistance circuit wire or connection can supply that many amps easily. But if you use a test globe the circuit needs to flow more like 1 amp (assume 12W globe, .5A if you use a 5W parking light globe) and a high resitance circuit wont allow that much current to flow and so the test globe may glow, but it will be dull .
Check your head light - is it bright? I fnot - see if the battery is OK.
My bet is that the earth/-ve wire has come loose or off from vibration during the ride.

No, no spare globes lying around the house unfortunately. The battery is good and the lights are bright.

Took the horn off the bike and checked all the connections. I tried to remove/re-connect them but they were pushed in firmly and wouldn't really budge much so my guess is they have not come loose. Will have to have another look at it once I get some spare time.

Will keep you posted on my results.

 

Hesh

Ok, well I used the multimeter this afternoon from work and I think the relay is stuffed.

I put the positive side on the relay connector that has the red plug coming from the original HD wiring connected to it (confused?) and I put the negative side onto the bike as an "earth" and I pressed the horn. There was a brief flicker on the dial but it didn't really register.

Next, I left the positive side on the same connector on the relay and then stuck the negative on the connector that has the main power coming from the battery (forgetting that is a wire from the positive terminal on the battery) and pressed the horn and the fucker went off and scared the shit outta me.

Must have created a conduit through the mutlimeter, bypassing the relay and making the compressor work. So.....I am guessing that the relay is the issue.

Multimeter still appears to work....just in case it wasn't supposed to after that nifty trick

 

Only problem is the horn has a 3 year warranty. I think I might have to contact them and query whether I can replace the relay without screwing the warranty or whether I have to send the bastard back to the US of A.

 

Hesh

 

Not really, from what you just described, there is power coming from the horn button, but not from the battery power wire connected to the reley input (30)

Power wasn't at the input terminal until you bridged it with the horn button and pressed it.

Check the main power supply feeding the reley from where ever it's connected .

Posative probe on meter to main power supply lead feeding the reley (30), and negative probe to earth.

(might have to have the IGN on for that to be live)

The reley could still be working, but with out power to the input terminal the compessor ain't gunna get any juice even when it's activated.

 Ok, will do. Sounds like a job for tomorrow. Every day's a school day :-)

 

Hesh

Problem solved.....so far anyway.

Tested the fuse on the Ohms setting and it gave me a reading of 0.01, which according to my technical friend  meant it was fine. If it had read 0L on the display, that meant it was fisted.

So.....maybe a cable issue, so I pulled the cable from the battery positive back through from underneath the tank and tested the wiring and it all appeared fine. Tested the fuse again and it failed. I'm like....What????

 

Anyway, long story short....in the end it was the fuse, why it blew I have no idea, but with a new 20A fuse in there and the wiring back it is all working just fine. If it blows again in such a short time, then I will look at replacing the cable.

Finally....a working horn again!

 

Hesh