Wiring AIRHORNS on a Tojo 60 series

[Megz]

Hi all,
I am trying to put air horns on my cruiser, but to no avail. the car has 2 wires going to each of the horns, I am wiring them up thru a relay how I think they should go, but I just can't get them to work properly. :(

What I want to do is just get rid of the old 2 horns, and wire my air horns in,, anyone tell have any ideas what I may be doing wrong?.
Cheers...

[wayne74]

youll prob find that the two wires should connect to your air horn pump ,most likely have a permanent positive and switched earth. if it doesnt work properly ya may have a voltage drop in the wires somewhere ,in that case when ya hook up the relay connect the original terminals to connectors 86 and 85 hook up a wire to 30 from the positive side (+) of the batt threw a fuse hook 87 to the horn pump(+) and run an earth wire from the pump to the body of ya car .

[Megz]

Ok, cheers, will give it a bash, what seems to be happening is that when I have it wired thru the relay, as soon as I try & plug the power wire from the horn onto the relay, the horns just have instant power & go off like a nun in a brothel..

But will try what you said to see if it is the same as I have got them wired, cheers mate..

[DamTriton]

Be aware that horns are usually set up as a switched earth, having a continuously "hot" +12v going to one terminal of the horn relay coil (should be one already there) and switching the earth to the other end of the coil.

Get a voltmeter an measure the voltage on the terminals of the horn when the button is pressed (better than that, get a mate to measure the voltage while you press the button ). Having had your fun, just connect the airhorn across the same terminals as the OE horns (splicing into the loom is a good idea, as it is a roadworthy requirement that electromechanical horns must be retained and servicable). Assuming the airhorn pump uses about 5 amp or so you shouldnt have any issues with the OE relay or fuses.

If you do have issues with fuses blowing, connect a relay coil up to the two wires you created from your splice, provide a fused supply to one side of the contacts in the relay, connect the other side to the positive lead of the airhorn pump, and ground the negative lead of the pump. (this may be what you are actually asking about...)