nVz

Greetings to all -

I have a '99 4Runner SR5. I tried to follow JasonB's instructions however I noticed these differences:

My passenger side horn has 2 wires going into it, as opposed to one.

My driver side horn also has 2 wires going into it.

I've cut the connector off the drivers side horn and tried to test both wires using a circuit tester. I was not able to determine which wire was the "hot" wire.

I've reconnected the passenger side horn, and attempted to use the horn. Nothing. The fuse is OK, the hazards still work.

Any ideas ?

Thanks SO much -

- Joe

rockfordrunner

hey i had the same problem. I'll go take a look at what i did on mines when i get home tomorrow.

Tacoma Dude

I have a Tacoma so I don't know exactly how much help I can be to you...

I installed my air horns just a few weeks ago and when I unbolted my factory horn I noticed the two wires too. I first thought one was the hot and the other was the ground. That was until I looked at the connections.

So rather than disconnect and try to figure out something I'm not sure of I used one of those wire tap thingies and just tapped into it while it was still connected to the factory horns and used that wire for my air horns.

yeah, I'm not sure exactly what they're called but it's a plastic box looking thing that has a latch. There are different versions of this thing out there but the principle is the same. You open the box thing in half (it's hinged) place the hot wire in the open groove and your new item wire in the opposite groove. You then latch this small thing shut and somewhere in the process a specially shaped blade goes down and cuts through both wires. This carries the current on from the stock accessory to whatever accessory you're adding.

Wasn't easy but I got both of those wires in with my air horn wire and just clamped the blade down to complete the circuit.

Easy!

I'm not sure if this is exactly what you want to do... probably a good idea to see what everyone else did.

Oh yeah, this way I actually got to keep my factory horn to sound w/ my air horn. All I have to do now is disconnect the air hose or the negative terminal and I'm back to stock

jx94148

Your horns are switched grounds as opposed to switched positive. All ground wires on Toyotas are white with a black stripe. One of those wires is always hot while the other runs to the horn button on the steering wheel where it is grounded when you push it.

I'm not sure which is which though. I'll look in my manual. I doubt it has changed from my old junk to your new stuff.

rimpainter.com

When you tested for the hot wire, was someone pushing on the horn?

jx94148

By chance are the wires you see green with yellow stripe and green with red stripe? If so Green/Yellow is positive and Green/red is Neg. to the button. Hope that helps.

nVz

I appreciate all the responses ! I am still in need of assistance...

On my 4Runner, all 4 wires (2 to each horn) are black with white stripes.

Yes, had the wife holding down the horn while I was testing for the hot wire.

Nope. See above.

nVz

anyone else experiencing the issue i'm having ?

- joe

midiwall

I've wired in air horns on my rig and didn't have the issues that you're talking about.

But, I may be able to help a bit...

On my rig (96 4Runner), the driver's side horn has two wires coming into it. With the connector in place, the wires are actually attached to one-another. One wire is coming from the horn button (or the horn relay) and the other wire is going to the passenger side horn. This is what's known as a "series" wiring scheme.

The horn draws it's power from one wire, and the attachment to the frame is the ground. It isn't using the other wire as ground. To verify this, you should be able to look into the connector that you cut off, and confirm that there is only _one_ metal connector ("blade") in there. If both wires were "needed' to fire off the horn, then you'd have two blades in the connector.

The "other" wire runs through a plastic loom just in front of the radiator, and then emerges from the loom to the other horn on the passenger side. On my rig, I think that there's only one wire on the passenger side... I'm trying to visualize it... maybe there is two. I can't really check until morning. If there _are_ two, then it continues on to somewhere else, but again, it's the electrically same wire that's coming _into_ the first horn.


I wired my air horns so that they go off with the original horns. This is what's known as a "parallel" scheme. I did that because I'm using horns that blast from an air tank, and I didn't want to be in a spot where the tank was refilling from the pump and I still needed a horn.

So... the bottom line here is that when you're testing for current, you should be testing between one of the wires and the frame. Don't test between the wires, that won't get you anywhere.

You should be able to find 12v at some point when the horn switch is depressed.

Try this... Hook the original electric horn back up and verify that it still works. If it doesn't, then something else is wrong.


Hope that helps...

Mark

nVz

Mark - thanks SO much for the reply. I've got a basic circuit tester, I'll borrow a more elaborate one to test.

I left the passenger side wires intact, however no horn. I'll attempt wiring back up the driver's side connector and test it, to verify operation before I open up that connector to see how the wires are set up within the connector.

I have tested between both of the wires and the frame previously with my basic circuit tester with the horn button depressed w/ no luck.

On my truck, both wires to the connector go into the wire loom - i'm contemplating popping that loom out and see where they lead to. I'll have more time over the weekend to check this out.. in the mean time I'm hornless

thanks again !

nVz

One of my co-workers that I carpool with studied to be an electrician back in the day. He looked at the connector i snipped off, then simply twisted the exposed wires together, then had me hit the horn. It works now. Go figure. So, right now, I have one working horn, all I have to do now is mount the compressor, ground it, and run that joined line to the positive of the compressor.

Now I'm thinking, I can rig another pair of trumpets to the passenger side, too