Horn Issues

Last issue before Wanda tries for an inspection.

Can't get the (new) horn to work. After a lot of testing:
1) Horn works when wired to the battery;
2) 2 wires to horn - one has 12 volts when ignition is switched on;
3) The other wire- Nothing, no power, no ground - even when the horn button is pressed. There is continuity from horn end of the wire to horn button (hub) wire. BTW - The little brass roller is making contact with the hub ring (Tuffy wheel).

The wiring digram isn't clear but I would think the steering column would be grounded and pushing the horn pad would close the circuit. But not so at the moment.

Shouldn't the metal of the steering wheel be ground?

Also one horn set-up came with a 3 wire relay, the other didn't and the manual doesn't show one for a 78. Do I need one?

Ideas? Thanks Grady

you could take the one wire that has power, run that to a relay, hook the relay up to the battery and a ground, then run two new wires from the relay to the horns. but this is assuming that the one wire that has power, is getting power after you push the horn button on the sterring wheel.

or try just running a jumper ground wire from the steering column to a ground source to see if thats your issue.

The thing is the steering column is grounded up to the hub. But the shaft that the hub splines onto is not grounded (plastic bushings?) . Thus hitting the horn button does nothing. It worked before and I can't figure out why not now (and I didn't take it apart).

No sure how I would run a new ground since it would have to turn with the wheel hub.

Could someone check their (metal) steering wheel bub and see if the hub is grounded. Thanks Grady

I'd check but my set up is different im sure. What about the horn themselves being grounded?

have you taken your steering wheel off? I had this issue on a 74 I had and it was in the colum, for some reason it was not grounding.

I had this problem on my truck. The circuit tested ok, but could not deliver the current required to drive the horn. Running the current for the horn through the steering wheel is not IMO good design. I added a solonoid activated by the horn button, and it has worked fine ever since.

Originally Posted by maachine

What about the horn themselves being grounded?

Important; yes I jumpered a known ground to the horn.

Originally Posted by dodgensince74

have you taken your steering wheel off? I had this issue on a 74 I had and it was in the column, for some reason it was not grounding.

I had the wheel and hub off and that is my problem, the column is not grounded.

Thus adding a relay won't help because I'm not connected to ground at the switch. It's the switch which make the 'ground short' that activates the horn (or relay).

Where does the shaft connect to ground???

It just occurred to me that I replaced the old school rag joint (not the can style) with a poly/plastic one. I wonder if that broke the shaft to steering box ground somehow.

Grady

I'm 99% sure the problem is in the plastic (non-conductive) rag joint. But I give up and wired a secondary switch in.

probably could have installed a jumper wire over that rag joint to complete the circuit.

did you try checking the ground by jumping the horn button to the steering wheel lock nut and then smack the steering wheel with you hand and did you check if you had voltage at the horn button?

Originally Posted by maachine

probably could have installed a jumper wire over that rag joint to complete the circuit.

Tried that with temporary jumpers but the horn still didn't work. But I did have ground continuity and a spark at the hub. And 12 volts at the horn end per my meter. I'll figure out a way to permanently jump the rag joint and add a relay. My temporary switch works for now and I'm wiring up the radiator fans today.

rag joint should have no affect on the ground since the bolts that hold it together still make contact. i gave up on going through the column so i wired the horns directly to a separate switch on the dash

Originally Posted by roadram360

rag joint should have no affect on the ground since the bolts that hold it together still make contact.

So you would think. I need to try to find my old one but IIRC it may have had an extra metal band that made the ground. Or there is enough paint it's interfering with the ground. I have a good ground on the steering box side but unless I jump to the column, nada. Grady