wiring horns

[Tractionman]

Hi all,new to this site and find it buzzing compared with certain others. anyway, the standard horns (2) on my lj78 are feeble, so have a pair of used but known working fiamms. disconnected old, and connected `new` - nothing. with 12v tester found both wires going to both original horns are live all the time and assume pressing horn button earths and completes circuit. Have had suggested the fiamms require more current to work, through a relay direct from battery.
How would I go about this, using existing wiring/connections, any help greatly appreciated, thanks.

Regards, John

 

[grantw]

Hello and welcome,
At the highest level explanation you wire the current horn live wire into the relay to turn it on and wire the relay directly to the battery and horns.

More detail can be found here: http://www.mp3car.com/the-faq-emporium/117895-faq-relays-how-they-work-and-how-to-wire-it-up.html

You should probably hook your horns up directly to the battery to test if they actually work before you go to the trouble.

Cheers,
Grant

 

[Tractionman]

Thanks for welcome and info Grant, horns were known working when given, but will double check anyway, my confusion is there are 2 wires to each horn on LC - both pairs live. do I take all 4 to relay as well as a new (fused) wire from battery to horns, and what numbers do I connect to on relay or will I require 1 relay for each horn. Many thanks, John

 

[Jon Wildsmith]

Thanks for welcome and info Grant, horns were known working when given, but will double check anyway, my confusion is there are 2 wires to each horn on LC - both pairs live. do I take all 4 to relay as well as a new (fused) wire from battery to horns, and what numbers do I connect to on relay or will I require 1 relay for each horn. Many thanks, John

Are you testing with the horns still connected? As the horn power is permanent live you will have the obvious positive reading on the 'supply' wires but also a positive reading on the 'return' wires due to it passing through the horn (assuming a coil of some sort). No current flows till the circuit is closed but the potential for it (the voltage) is there all the way to the switch or relay. With the horns disconnected only one set of wires should appear live? As Grant said, check the new horns work with direct power first, sometimes the simple stuff will catch you out!

 

[Tractionman]

Hi Jon, tested with no horns connected at all, direct to each of the spade connectors at end of wiring, test screwdriver lights up when held to each of the 4 ends.
I know LC wiring can be a little quirky at times, but I am surprised both wires to each horn are + + and not + - as expected. Both sets of horns do not seem polarity sensitive either - LC ones work connected any way and fiamms not marked so assume the same. My mate is positive they worked, but will check direct to battery tomorrow as Grant suggested, as you say the simple stuff etc.... appreciate your help guys.

Regards, John

 

[Tractionman]

Yep. Fiamm horns work (loud) connected direct to battery, and the 2 pairs of wires (LC loom) going to each original horn are all live, this is strange, if they were + - , I could easily follow the diagram supplied by Grant, but with all +, I don`t know which ones to connect where on the relay. If I use 2 relays, one for each horn, I have 2 lives opposed to 4 to each horn, so I`m still non the wiser. HELP!!
John

 

[Jon Wildsmith]

That does sound strange, can you use a multimeter to check voltages though rather than test lamp which might be misleading somehow?

 

[Graham]

I would never use one of them screw driver indicator things.

Rather get a test lamp, make one yourself with a 12v bulb in a holder.
Some thing like a 21W indicator lamp.
Some thing substantial to show that it is not merely voltage present, but there is current available also.

Gra.

 

[Tractionman]

Thanks guys, will sort something and retest when/if rain stops, your assistance appreciated.
Regards, John

 

[Tractionman]

Borrowed a multimeter - all 4 wires, 2 to each horn, read 12.2v a simple? job of changing horns has become ****. any suggestions, other than sling `em and forget it - already had that, lol

John

 

[Shayne]

Perhaps this will help i only skimmed through it but it suggests to me the standard horn may be earthed by its mounting bracket so try connecting the live to your fiamms and bolting your earth to the old bracket ?

http://www.forums.ilambretta.com/viewtopic.php?f=2&t=34896

 

[Chas]

You could always leave the original horn as is and wire in a separate circuit and an extra switch/button for another horn.

 

[Tractionman]

Thanks for response guys....

Shayne, initially I changed the horns over (thinking this was a 5 min. job)and had the fiamms bolted to the same LC mounting points so they were earthed, - as there are no seperate earths, only lives, as stated previously reading 12.2 volts, this is where it goes t*ts up. I don`t understand why there are two LIVE wires going to each LC horn that work (quietly) and when I connect same to fiamms - nothing. this is some strange wiring system??

Chas, as far I as can see, that would work, but I would like to keep the same controls, having seperate switches/buttons could get awkward.
Ah well back to square one, thanks for suggestions - keep em coming please.

John

 

[Thommo]

Hope I'm not out of line, but could this be why the original horns don't work??? Maybe try testing original on battery and check that a relay hasn't shorted out?

 

[Tractionman]

Thommo, you misread (see previous posts post) they work, but are feeble compared to ANYTHING else, on or off the road, hence the reason for changing to something louder, and boy are are these fiamms LOUD, thanks for your input anyway

John

 

[Steve H]

You could use one of those live wires to connect to the switching side of a relay and run a wire to earth to get the relay clicking when you push the horn button. Then run a wire from the battery through a fuse to the live side of your horns. Earth the other side of your fiamms to a good earth point and when you push the button they should work. I did the same on my Colorado and it works fine. You will need to insulate the other wires and tie them up out of the way to prevent any mishaps. HTH

 

[Tractionman]

Steve H, I like the idea and in my mind I can see that working - worst case blow a fuse or two, (must get more spares.) Got a shitload of work come in after a lull, will get on this mod asap. will let you know, thanks,
John

 

[fridayman]

Do the new horns earth via the mounting bracket, or a negative wire?

Btw this thread reminded me I had a Stebel Nautilus in a box so I fitted it this morning. It's pretty loud, but not so loud that it will cause heart attacks.

 

[Tractionman]

, but through a relay when wired in properly.

John

 

[Tractionman]

Fridayman, sorry a glitch somewhere. horns tested with + & - from battery and then swapped, worked both ways so not polarity sensitive, just a simple + - but through a relay when wired in properly

John