horn wiring issue

[AU Bronco]

I am trying to wire up and air horn using the horns relay but the stock button. I got it to work and shortly after i think i blew a fuse. The manual says "fuse location"="headlight switch". I checked the wiring up to the point of where the radio is and grounded the blue/yellow wire...it worked..then i jumper to the horn button to make sure it was grounding..it worked... so my problem is after the button and before where the radio goes...i assume its bad fusable link but im not sure where it is and i dont want to have to take everything out. Thanx for your help.

 

[oleguy74]

after market wireing or stock?

 

[AU Bronco]

its stock

 

[oleguy74]

no fuse.wired directly to starter solenoid.horn relay may be shot.

 

[AU Bronco]

im not using the stock relay im using the one that came with the horn bc i kept blowing the stock ones

 

[DirtDonk]

Early (up to about '74) models used the headlight switch as it's power source and no relay. Your '75 gets it's power straight from the battery via that larger Yellow wire from the starter solenoid to the relay. Only three wires are used because the relay is grounded through it's case.

Does your new horn's relay have the industry standard markings of: 30, 85, 86 and 87 (maybe even an 87a) molded into the plastic near the terminals?
Are you mounting it near your stock relay so you can access the wires easily?

If so, then:
#30 connects directly to the battery. You can use the Yellow wire, as-is.
#85 connects to the horn button. Use the Blue w/yellow wire.
#86 connects to any 12 volt source. Rig up your own or find an existing one.
#87 connects to the horn, or air pump. You can use the Yellow w/green one.

This should get you there. If this is a monster pump, you might want to upgrade to larger gauge wire between the battery (30) and the pump (87). Otherwise, you should be good.

Paul