1986 MJ horn

[Dom U]

So trying to figure out what the previous owner did here with the horn as I'd like to restore it to original function.. wiring isn't my strong suit trying to figure out if he tapped into the original horn wiring or all this is just added?

 

TIA

 

Horn button added by PO

 

One wire leads here kind of by where the foot brake should be how ever PO cut that off...

 

 

2nd wire leads here under the steering column.

[Dom U]

Also under steering column is a red wire, black and green wire along with a in line fuse that has nothing in it and the wires seem to go no where.

 

[Dzimm]

I've never tracked the horn wiring anywhere but I can say typically it's only got a single wire.  Both the horn button and the horn itself are fed positive voltage, the horn body is grounded to the truck body and the horn button touches the metal steering column for ground when pressed.  

 

I'd try to get the factory horn working as intended instead of trying to figure out the POs wiring.  Unless you are just going to remove their crap entirely.

 

 

[gogmorgo]

I would imagine you can probably just remove the added button and repair whatever’s wrong with the horn button.

Depending on the style of steering wheel there’s a couple different setups of contact wheel that like to go bad with time and use. But all the button does is connect the wire to ground, completing the horn relay trigger circuit to send power to the horn.

Depending on which wires were tapped into, either they’re pulling an alternate source of power and connecting it to the horn wire, or else tapping into the trigger wire and connecting it to ground. My guess would be the latter, based on it looking like they tapped a wire going to the connector for the multifunction switch. Good news though is whatever they did, it looks like they did in parallel with the factory wiring instead of hacking it out and making it new, so hopefully all you need to do is pop those wire taps off and fix whatever issue with the factory wiring they were circumventing.

[Dom U]

1 hour ago, Dzimm said:

I've never tracked the horn wiring anywhere but I can say typically it's only got a single wire.  Both the horn button and the horn itself are fed positive voltage, the horn body is grounded to the truck body and the horn button touches the metal steering column for ground when pressed.  

 

I'd try to get the factory horn working as intended instead of trying to figure out the POs wiring.  Unless you are just going to remove their crap entirely.

 

 

Basically what I want is it all functioning as it should. I want to eliminate the PO horn wiring and return it to stock .

[Dom U]

1 hour ago, gogmorgo said:

I would imagine you can probably just remove the added button and repair whatever’s wrong with the horn button.

Depending on the style of steering wheel there’s a couple different setups of contact wheel that like to go bad with time and use. But all the button does is connect the wire to ground, completing the horn relay trigger circuit to send power to the horn.

Depending on which wires were tapped into, either they’re pulling an alternate source of power and connecting it to the horn wire, or else tapping into the trigger wire and connecting it to ground. My guess would be the latter, based on it looking like they tapped a wire going to the connector for the multifunction switch. Good news though is whatever they did, it looks like they did in parallel with the factory wiring instead of hacking it out and making it new, so hopefully all you need to do is pop those wire taps off and fix whatever issue with the factory wiring they were circumventing.

What I'm trying to figure out is what he taped into one wire I figured out is just grounded to firewall area, the one that runs up under steering column goes to a connecter but looks like he might of hacked it right at the connecter leaving maybe half an inch of wire if I cut his off..

[Dom U]

This wire leads to horn button he installed is this part factory or added? 

[gogmorgo]

Those wire taps are typically used to make a T-splice, with the original wire you’re tapping into running straight through with only minor damage to the insulation, but it shouldn’t be cut completely off... although I suppose I guy could use it in place of a butt splice if he really wanted. But if done “properly” (I’d argue there’s no proper way to ever use that sort of connector) then you should be able to just pop the connector open and pull it off, then wrap some electrical tape around the cut insulation, and it should be fine. If however the wires were cut, this is one of the few places I would use a crimp-on butt connector, provided of course you can find both ends of the cut wire.

If one end is grounded, then that means that is is just bypassing the horn button. Fixing the horn button will require pulling the steering wheel and the steering lock plate. It can be done without special tools, but if you can get a steering wheel puller and the steering lock plate tool, it’ll make the job much easier.

 

As an FYI, those wire-tap connectors though are a sure sign of a hack job. Aftermarket installers like to use them because they’re quick and cheap, and usually they’ll last long enough the customer won’t complain if they fail. But they create stress points where the wires will crack if exposed to too much vibration, and they’re not even close to sealed. Which means that the trailer manufacturers who also love to use them exposed on the outside of the vehicle are just inviting in the green death... so you’ll come back in and spend more money getting the thing fixed. /rant. Don’t use ‘em.