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Peterski

Horn blows a fuse (Fiamm mini blaster duo)

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Peterski

Hi guys,

 

Decided to upgrade my 2015 NC750X with a Fiamm mini blaster duo horn (which is basically 2x AM80S horn), which came with a relay and a diagram in the box.

Since I know next to nothing about installing stuff like that, I relied on my mechanic - asked him to install and wire the horns during the maintenance check up.

 

The horns seemed fine until the next day, when I used the horn for a longer beep (around 2 seconds) while braking. It blew a fuse which switched off the horn, the dashboard lights, the indicators and the tail light. Great fun when riding through the city centre's heavy traffic at 7PM.

I went back to the mechanic who replaced the fuse but "couldn't say" what caused it. I was hoping that maybe it was a once off, a coincidence, but that's not the case. Happened again on Wednesday in similar circumstances.

 

The blown fuse is the 7.5A horn/stop light fuse. Replacing it is not  a problem, but I don't want to do it every few days (even though I've learned how to do it myself, very proud of it ;-)) - for now I replaced it with a 10A (since I couldn't find any 7.5A locally). Probably not the best idea, I definitely don't want to burn my horn button, but but I'm hoping it is safe to use it for a 20 mins ride to halfords to get 7.5s. 

 

Anyway, I suspect he didn't wire it properly - when looking at the battery terminals I was expecting to see the connectors for the horns attached, but the only things connected to the battery are an accessory harness and an Oxford oximizer cable (which I don't use). I think he just replaced the stock horn with one of the FIAMMs and then put a wire to the second snail - without bothering with the relay. And since they take some 9 amps when used together, a longer toot will always blow the 7.5A fuse... 

 

However, before I go back to him and accuse him of not doing it properly, I'm thinking of checking it myself (and learning something in the process) - but I'm not sure where to start. Where should I expect to see the relay that came with the horns - if it was installed at all? Would it be close to the battery or somewhere near the horns? I expect that I'll have to remove the side panels to see the cabling?  I've looked through the forums and some threads indicate I should find the cables on the left side of the frunk? Or can I somehow check it without removing panels?

 

Thanks

Edited by Peterski
typos

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Dunnster

These forum links should help.  HTH

 

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ste7ios

It’s really simple... The fuse is blown  because the needed current by the new horn is bigger than the one the lines can tolerate. It protects you from overheating, fire...

 

I guess he didn’t use the relay at all...

 

I would suggest to find an engineer / electrician that knows what he is doing...

 

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embee

As they say.

For horns like that you need a dedicated power supply direct from the battery, with suitable fuse near the battery and heavy enough wiring for the current. The relay can be sited anywhere along this power line, wherever is convenient for the horn push connection or where space permits. The original horn push is used to energise the relay coil only, that takes something of the order of just 0.1A. 

 

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pjm
giley

i bet he just tapped into oem horn... track oem horn wires and see if it has been wired direct... you could then use that as trigger for relay and run power from battery yourself

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Andy m

My bet is the relay is OK, just slung across the original horn wires. Where he's got the power for pin 30 or the earths for each horn will be a laugh. Look for Scotchlocks. 

 

Any bets if Peterski pulls a wire off one horn the other stops working?  Will there still be clicking from the relay? 

 

It never ceases to amaze me that professionals who can rebuilt a gearbox will often struggle to make a spotlight work. Teaching sparkies to stop fluids leaking is usually easier. 

 

Andy

  • Haha 2

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Peterski
5 hours ago, Andy m said:

My bet is the relay is OK, just slung across the original horn wires. Where he's got the power for pin 30 or the earths for each horn will be a laugh. Look for Scotchlocks. 

Any bets if Peterski pulls a wire off one horn the other stops working?  Will there still be clicking from the relay? 

It never ceases to amaze me that professionals who can rebuilt a gearbox will often struggle to make a spotlight work. Teaching sparkies to stop fluids leaking is usually easier. 

Andy

 

There was a relay in the box with the horns, so I'd expect him to use it for installation - the question is where wired it to.

 

I think I mostly understand the principle behind it and how it should all be connected but I'm not brave enough to try and fix it myself. I'll look for a better expert ;) This guy came highly recommended, but as you say - he's probably more of a mechanic than electrician.

 

In the meantime, I'll probably just carry some spare fuses with me - or try to disconnect one horn and see what happens.

 

Thanks for all your replies, guys. Much appreciated.

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Andy m

If he used the relay it'll be cable tied in the original horn position, the Honda wires go straight on.

 

Andy

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SteveThackery
On 2/22/2019 at 20:16, Peterski said:

 

Since I know next to nothing about installing stuff like that, I relied on my mechanic - asked him to install and wire the horns during the maintenance check up.

 

 

I don't know your mechanic, but I've got to say that asking a mechanic to do anything electrical is asking for trouble (that applies to car and bike mechanics).  It rarely ends well.  The trouble is, very few of them know anything about electrics, and what's worse is that you've no way of knowing in advance whether they are competent or not.  The chances are not good at all.

 

It would be much better to find an automotive electrician.  Alternatively, undertake the job yourself, having asked on here for guidance if you feel you need it.  Honestly, electrics are FAR easier than most people imagine, and (I think) easier than most mechanicking.

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DelBoy
Posted (edited)

I had the same problem with a single Fiamm using original horn connections.

 

I have since fitted a Denali Sundbomb mini horn (Similar design) that is specified as a direct replacement for the original.

 

NO problems with this one (Except it is not as loud as it needs tuning).

 

 

Edited by DelBoy

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ncx19

as an electrician ... as others mentioned - use the factory horn lead to activate a new accessory relay coil. Feed the horn direct from the battery via the relay contacts.

Put a fuse in an accessible location for the battery-horn lead.  before or after relay contacts  doesnt matter.

I prefer to use proper diameter sized plastic split loom to cover new wiring, to prevent chafing of the conductor's insulation. (like what you see on other bike wiring).

Use appropriate crimp connectors on relay, battery, horn. Give them a tug after crimping to ensure they are secure.

 

relay coil - oem horn wire, ground.

relay contacts - battery, new horn.

 

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