Musical air horn help

[LaFleur]

Hi all,

after many months of threatening my wife of my intentions to buy a musical air horn I was pleasantly surprised to find one in my Christmas stocking. The issue is that it was not supplied with any wiring instructions and after searching it appears many are not.

It was supplied with what I assume to be a relay but it has been many years since I last looked at such a device and would appreciate some help.

There are four terminals each labled 85, 86, 87 and 30. Looking at the attached diagram I have drawn a blank and would like to understand how it wires in. On the compressor there is a further + and - terminal. My guess work so far is as such:

30a feed with inline fues to terminal 30
Switch to passenger cabin connected to 86 (what rating?)
85 to + terminal on compressor
87 goes to ???

This is all probably incorrect and will please Mrs La Fleur as it is not her idea of a worthy modification. Do I even need to use this relay? Would it not be possible to wire the compressor - to chassis and + to battery with an inline fues and switch?

Thanks

LaFleur

[steveo3002]

does need the relay as the compressor pulls some amps

the relay is a standard one, google has diagrams same idea as this one , but horns instead of lights

http://www.offroaders.com/info/tech-corner/reading...

[LaFleur]

steveo3002 said:

does need the relay as the compressor pulls some amps

the relay is a standard one, google has diagrams same idea as this one , but horns instead of lights

http://www.offroaders.com/info/tech-corner/reading...

Thanks, that is exactly what I needed (and hoped would be included in the box!)

[Lord Flathead]

As Steveo says you will need the relay. Otherwise the speed of tune will drop significantly due to volt drop and you may also burn out the wiring to the horn push. Make sure you have fuses inline on both the control circuit (the wire that feeds the coil of the relay although this should be catered for in the cars wiring for 'horn') and also for the power circuit (the thicker wire which goes straight from the battery to the relay). The purpose of a fuse is not to protect the equipment connected to it, but moreso to protect the cable that feeds it from risk of electrical fire.

[mad4amanda]

87 goes to the compressor of the horn! ie out put of the relay
86 to earth
85 is switched feed
30 is power to the relay fuse rating is the wattage on the compressor divided by 12 then rounded up slightly ie if its 65w it would be a 7.5 amp blade fuse
http://www.ehow.com/video_4874551_wire-relay.html might be of help

[LaFleur]

The more I look at this the more I worry! There is no details about the rating on the compressor, all it shows is 12v! Nothing included in the box and I had noticed nearly every place I had looked they all stated "instructions not included", why?!

[Caruso]

What tune does it play?

[LaFleur]

La Cacuracha, one did not want to appear common and play Dixie!

La Fleur

[Eggman]

How old is the car that you intend fitting them to?

[eliot]

LaFleur said:

The more I look at this the more I worry! There is no details about the rating on the compressor, all it shows is 12v! Nothing included in the box and I had noticed nearly every place I had looked they all stated "instructions not included", why?!

its only a simple relay. post above by mad4 is correct. 10-15a fuse will be fine assuming your wiring is rated above 15a. I would get 25a rated wire.

[LaFleur]

Eggman said:

How old is the car that you intend fitting them to?

A year old, why?

[LaFleur]

eliot said:

LaFleur said:

The more I look at this the more I worry! There is no details about the rating on the compressor, all it shows is 12v! Nothing included in the box and I had noticed nearly every place I had looked they all stated "instructions not included", why?!

its only a simple relay. post above by mad4 is correct. 10-15a fuse will be fine assuming your wiring is rated above 15a. I would get 25a rated wire.

10-15 is a large range and if it only requires 7.5 then I have no protection!

[eliot]

LaFleur said:

eliot said:

LaFleur said:

The more I look at this the more I worry! There is no details about the rating on the compressor, all it shows is 12v! Nothing included in the box and I had noticed nearly every place I had looked they all stated "instructions not included", why?!

its only a simple relay. post above by mad4 is correct. 10-15a fuse will be fine assuming your wiring is rated above 15a. I would get 25a rated wire.

10-15 is a large range and if it only requires 7.5 then I have no protection!

so stick a smaller one in then. worst that will happen is that it will pop. Its more important that the wiring is beefier than the fuse, not the other way round.
i had air horns once and the pump seemed fairly meaty.

[Eggman]

LaFleur said:

Eggman said:

How old is the car that you intend fitting them to?

A year old, why?

They're illegal on vehicles registered after August 1973.

[LaFleur]

Eggman said:

LaFleur said:

Eggman said:

How old is the car that you intend fitting them to?

A year old, why?

They're illegal on vehicles registered after August 1973.

It would be for show use only and not as a replacement for the main horn.

[Eggman]

That's OK, then!

(Their main application these days is on sandwich vans plying their trade round industrial estates, so take a few cartons of Kit-Kats and a tray of Tizer along with you and they might pay for themselves )

Edited by Eggman on Saturday 25th December 22:05

[TheLurker]

mad4amanda said:

87 goes to the compressor of the horn! ie out put of the relay
86 to earth
85 is switched feed
30 is power to the relay fuse rating is the wattage on the compressor divided by 12 then rounded up slightly ie if its 65w it would be a 7.5 amp blade fuse
http://www.ehow.com/video_4874551_wire-relay.html might be of help

^^^ Will work fine. As has been said, make sure the wiring is up to the job; pins 87 and 30, plus the -ve terminal on the compressor should be 15-20A rated, I would have thought (never played about with these things). Make sure the fuse is a smaller value than the wiring - preferably by at least 5A.

All the other wires (and switch) need only be small ones - capable of 3A. Again, make sure there is a fuse as near to the power supply as possible(1A). For all the wires, you can go bigger than I have suggested.

[the_scorpion]

How times have changed.
I used to have a set of triple air horns on an old Citroen in the late eighties and they just connected to the old horn wires pos to pos and neg to neg and they worked fine. From what I remember they didn't come with a relay or instructions.