# Relays and airhorns....



## Waleem (Nov 1, 2006)

Hi guys
I have bought a set of airhorns to replace the pathetic standard item on my 1996 Ducato. Whilst at it, I also want the horn to only work whilst the ignition is on, as at present, every time you lean on the push, it sounds (Even on campsites in the middle of the night !!  
The wiring to the relay seems straightforward, but I have a couple of questions:

1. The standard horn has red/grey and black/white wires-is the red/grey the positive ?(not sure which shouild go to which terminal)

2. If I wire the permanent live relay terminal to an ignition feed, will this stop the horn working without the ignition on ?

Sorry if these seem like daft questions, but electrics are the work of the devil..........
:lol:


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## Zebedee (Oct 3, 2007)

Take care Waleem!!

I *think *it's illegal to wire air horns into the standard horn switch. You have to use a separate switch, but even then some airhorns are illegal in some countries . . probably the ones that play a longish tune??

I'm not certain about any of this, but I'm sure I heard something like this somewhere. You would be wise to check first, and I'm sorry if I'm wrong but it might just save you a hefty fine.

Cheers

Dave


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## boosters (Nov 10, 2006)

*ref air horns*

the quick and easy way to wire the horns are put one of your original horn wires to 85 the other to 86,from terminal 87 to the horns and supply your ignition feed to terminal 30.When you press your horn button with ignition off the horn will not blow only the relay will click.
If you wire as above please make sure that the ignition feed is of a good amperage supply and if through a fused circuit make sure it is capable of standing the amperage of the horn compressor.

Terminal
30 Good amp ign supply
87 To Horns
85 original horn wire (either)
86 original horn wire (either)

Hope this helps
Regards
Alex


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## Waleem (Nov 1, 2006)

Thanks guys

Alex-where would be a suitable place to take the ignition feed from ? I was intending to scotchlok into an unknown underbonnet wire which is ignition live only-I am now starting to wonder. I will be putting a 20A inline fuse in the wire as recommended by the manufacturer.
Many thanks for your help.

Dave-its only the musical ones that are illegal-mine are just basic two tone ones.


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## boosters (Nov 10, 2006)

*air horns*

Hi Dave
Firstly do not use scotchlocks they will cause more problems than enough,do you know what wattage or amperage your air horns are,what vehicle is your motorhome based on eg Fiat 2.8 jtd.
If you tell me what vehicle i will look at a wiring diagram and advise where to pick up your ign feed
Regards
Alex


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## teemyob (Nov 22, 2005)

*Horny*

Hello,

I wired the our Air Horns with a 30 Amp supply from the battery (Fused). Then connected a feed from the original cab horn (live to), into a seperate push button, then onto the relay.

Result is that if you press cab horn - that's what you get "bip bip"
If you press the large red button you get - BLARP BLARP along with blip blip along side.

The Air horns will not operate without the ignition on as The Merc horn only works with ignition on. Not sure about your chassis.

Any help?

Trev


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## Waleem (Nov 1, 2006)

Alex
Many thanks for the advice. The horns just say "Stobel 12V" but no reference to amperage-it just says to use 2.5mm wire and a 20A fuse. The van is a 1996 Fiat Ducato 2.5 TDI. (Left hand drive, which means the switchgear etc is already on the side of the van near the horn.)
Really appreciate your help !

(Trev-The Ducato horn works all the time, which is one of the things I want to change! It really isnt worth keeping the original as it can barely be heard!!)


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## 97993 (Mar 5, 2006)

> mine are just basic two tone


I assume you mean Dual tone, ie two horns operating at the same time
two tone horns (alternating) are an MoT failure
Geo


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## vicdicdoc (May 14, 2005)

["Geo"]


> two tone horns (alternating) are an MoT failure
> Geo


Yeah - but they don't half clear the road infront of you :lol:


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## mangothemadmonk (Aug 6, 2006)

Not always Vic.....


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## boosters (Nov 10, 2006)

*air horn wiring*

Hi Dave
sorry for delay in replying,the best place to pick up a good ign feed is of the back of your ignition switch,test with a test light when ign is switched on,follow wire part down loom from switch and solder your wire to original wire,connect this to terminal 30 on relay and make sure you put good quality fuse holder in line.
Hope this helps
Regards
Alex


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## Waleem (Nov 1, 2006)

Thanks Alex-should be straightforward. Really appreciate your help!


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