I have a 1975 F250 I just picked up, and I am having a problem with the electrical circuit for the horn.

Here is my question. After pulling off the wheel, there is a "plunger" button, in the column, that seems to make contact with a metal ring in the back of the steering wheel. I assume that by pressing the horn button, a circuit is completed to ground.

My problem is that the circuit is completed anytime the wheel is replaced. (horn will honk constantly) Upon taking the wheel back off, I notice that the "ring" that the plunger contacts( on the back of the steering wheel), has continuity to other parts of the steering wheel, that would constitute a complete circuit?

My question is this....should there be some type of insulating material between this "ring" and the area that the steering rod comes through. If not, then how is the circuit broken, when there is obviously a short from one place to the other?

 

The "short" should be thru the horn switch in the wheel.

 

Use an ohm meter and check the resistance between the two wires coming off the horn button (bar) itself. It should read open or infinite resistance. If it reads 0 ohms or anything less than infinite then the horn switch is bad. The switch should connect from a spade lug on the wheel to the metal hub of the steering wheel. Usually a spring lug that goes into one of the wheel pulling holes.

 

I am no electrician by any means, but here is what I am finding. Using my meter, I checked for continuity/ohms, in the actual switch. It is working correctly.

My problem is that the hot lead in the steering column, is connected to a metal "spring/plunger" I assume used to maintain contact as the wheel is turned. This hot lead, is contacting the same part of the steering wheel, as is the ground lead inside the wheel.

So what I have are two leads from the switch going into the steering wheel. One lead connects to a male end, which leads to a metal ring on the back side of the steering wheel. The other lead connects to another male end, which is connected to another metal ring on the back, as well as all other metal on the steering wheel. Between the two rings there is no continuity, they are insulated via some plastic. Between the inner ring and everything else there is continuity.

I assume that the hot lead with the spring/plunger should contact the one ring, and as the switch on the wheel is depressed, the circuit is completed to ground, causing the horn to honk.

My problem is that the spring plunger, is contacting the same lead as the ground side, so I have a constant switch.

I can't see how there could be any adjustment, but to me it seems to be contacting the incorrect part of the steering wheel.

I have some pictures if anyone would care to see them off forum. I am puzzled, and wonder if this could be the wrong steering wheel?

 

The steering wheel from my '74 had a single contact ring to match to the single brush(spring-loaded pin) in the column, so I suspect that you have an earlier model wheel? I am intimately familiar with the situation because I was trying to fit a Momo wheel to mine, the Ford-Momo adaptor that I got for it had 2 contact rings, so there was a difference. I measured the ring diameters and found that the brush would just about line up between the two rings perfectly, so no-go on that adaptor (or wheel)!
There were a couple of 73-79 wheels on ebay recently, JFWIW. Steve

 

If this is a stock wheel you have a steering wheel from a cruise control equipped truck. As is the turn signal switch. There should be 3 connections off the horn button. 2 to male blade connectors and the third to the hub of the steering wheel. If you don't have cruise, figure out which spade lug is for the horn by grounding it to the hub and connect between that one and the hub.

 

I was looking around on the internet, and did see that the steering wheels for my year model (1975) seemed to have only one contact ring, so I suspect that this one had been changed.

Previous owner installed a pair of air horns with a remote button, instead of fixing it the correct way. I hate when that happens!

Thanks for the posts, I will look for another steering wheel.

 

The wheel should work if you connect it properly. Figure out which tab is for the horn and connect to it. Later if you want to install factory cruise, you've got the most expensive parts already.

 

Supercab...I think I understand what you mean, but this particular steering wheel does not have any provision for cruise control.

Previous post describe his wheel having only one contact ring on the back, which would make much more sense to me based on the wiring, etc.

Ah the joy of owning a pre-owned old truck!

This forum list is great! Very helpful so far....now to find a correct wheel!

 

Actually, if you get a new wheel, your horn button (bar?) could be swapped over.

 

Yes, that is what I am hoping to do. Off this morning to try to find another wheel. Don't have time to wait on an ebay auction on anything, so to the salvage yard I go!

Thanks for your help