Horn Wiring?

[Hoosierman]

I do have the electrical and vacuum diagram, but I can't see to find a diagram for the horn wiring after the fuse box to the steering column. I have no clue what wire to look for, or even if it is there at all. The PO removed the original steering wheel, installed an aftermarket one, didn't bother to wire up the horn button at all. So I removed the steering wheel and can't find a connection anywhere. I really want to wire the dual horns up. I've followed the DB to the Y LB D all the way to the 20A fuse, and that's as far as I'm seeing in diagrams. Any suggestions would be greatly appreciated!

I'm tempted to just wire up a new horn button to the dash, but I really want to find an original steering wheel and button.

 

[RobbieD]

I think that it makes a difference, on whether your truck originally came with cruise control, or not.

 

[Hoosierman]

I see absolutely no indication whatsoever to suggest it ever had cruise control.

 

[RobbieD]

With cruise there would have been a horn relay, triggered by the steering wheel switch; without cruise the steering wheel switch sent power directly to the horns without a relay (which involves more current, BTW).

"If it were me"

I'd go on ahead and add the dual horns that you're wanting, using a relay to power them, which is switched by a simple pushbutton in the cab.

When you do find yourself a stock steering wheel, it would be easy enough to wire your previously added horn trigger wire to the stock horn switch.

I have to think that would be kits out there, reasonable, for the wire, parts, and hardware that you'd need (appropriate gauge wires, fuse and holder, relay and socket, terminals, misc. screws and wire ties).

"And furthermore"

Doing the horns project would be a great time to also convert your headlights over to be driven by relays.

Same kind of work, same kind of parts, and same real estate.

The bulk of both projects would be behind the radiator support, with only a horn trigger wire being ran into the cab.

 

[Curious Hound]

Seems like the Y/LB D should come from the fuse and ho to the switch. Then the DB goes from the switch to the horn. Then yhe horn would be grounded locally, maybe by its mounting screw to the body. But I don’t have the exact 1988 drawing in front of me. For some reason, that diagram is often on the page with the cigar lighter.

 

[Hoosierman]

The original dual horns are still present and I've tested them, they work. I'm merely curious for now what color wire(s) go from the fuse box to the steering column for the horns. I am thinking it's yellow but I'm not 100% positive.

Edit: A few months ago, I did a full upgrade of the headlights with Koito K4s, new harness with relays, and refreshed all the grounds-- and that was when I took the time to evaluate and clean the connections on the horns- as well as the grounds for everything.

 

[RobbieD]

Without cruise, Yellow with Blue dots should be the color of the original +12 volt supply wire.

Dark Blue would be the switched wire to the horns.

Without cruise, the power wire (Yel/Blu) runs straight from fuse 16 to the steering column; there's no inline connector to find it at for tracing purposes. I suspect that the previous owner probably just cut the original horn wires where they exited the dash harness- look close where the wiper and lights' ending harnesses break out of the main harness.

The Dark Blue horn switched wire you can find under the hood at C120 (gray 8-pin), driver's fender well. See drawing 44-2 in your EVTM on page 44.

If the Dark Blue wire can be located in the cab, it'd work great to convert for use as the trigger wire from the cab to an added horn relay.

>>> If you've already got a headlight relay conversion job under your belt, adding a horn relay should be easy.

 

[Hoosierman]

That's the thing, I'll look again, but after the fuse box, I couldn't find any signs of a Y/LB D wire or DB wire. No daylight left today though.

 

[Curious Hound]

That's the thing, I'll look again, but after the fuse box, I couldn't find any signs of a Y/LB D wire or DB wire. No daylight left today though.

The DB wire doesn't go to the fuse box. It goes from thehorn switch in the steering column out to the horn. Here is tje vircuit diagram from 1993. The connector numbers are different. But the wire colors and circuit design are the same as what your truck should have. There should be a connector somewhere that they disconnected when they removed the original steering column.