Horn contact question ('67)

[Silverbullit]

No horns.
Bench tested both horns, good.
Proved relay, good.
Proved wires, good.
So with the horn pad off, if I manually ground the contact ring to the steering column, works great.
With horn pad on, nothing.
I have a new contact button. So, my question is: What exactly does the contact button do?
Does it "make contact" internally, like a switch, or merely connect 2 components?
Seems like the contact button is always in contact with both the contact ring and the horn pad.
(my search did not produce an answer)
Thanks in advance.

[Rich Lambert]

The contact and the ring are always common. The circuit is completed when one of the round brackets on the back of the center of the horn pad touches the other bracket, which is supposed to be grounded.

I just went through something similar on my '66. After 5 hours of doing all the things you did, I think I got it. From what I could tell on the schematic, ground potential should come up from the steering rack through multiple joints in the steering shaft to the column. When you press the horn button it completes the ground circuit to the horn relay coil and fires the relay. When I pressed the horn button the horns wouldn't work unless I jiggled the wheel back and forth...not a good thing to have to do if you need to warn off someone RIGHT NOW. I'm assuming that after all these years there's not much clean metal in those joints. My not so elegant solution was to attach a ground wire to the column that comes out of the dash and attaches to the chassis in the trunk. At first it appears the column is grounded by the 2 bolts with the tab washer, but they're isolated by rubber grommets where the bolts go through the column and into the chassis. I drilled a small hole in the column in a spot that's covered up by the fiberglass steering shaft cover, attached a terminal with a self-tapping screw, and the other end went to the ground stud just above he fuse block. And...I have horns now without having to change lanes.

To test if this will work for you, see what kind of resistance your getting between chassis ground and the column. If it reads open, attach a jumper from the column (not the bolts) to ground and see if the horns work. If that doesn't work...never mind.

If you want a picture, let me know.

[andyjboy]

Brian - has the horn worked in the past ?

If not, can you post a picture showing the underside of the hornpad centre (to see if anything's obviously missing) ?

[Silverbullit]

No, the horns have never worked by pressing the steering wheel pad.
So, if I understand, the contact button rides in constant connection with the contact ring and the back of the horn pad, and is not itself a 'on-off switch'.
So, my next test will be to reinstall the horns and steering wheel, and manually 'connect' the contact button to the steering column (ground) and see what I get...
Here's the back of the horn pad....and, thanks all.

[Rich Lambert]

To test that the horn pad is functioning before you put the wheel back on, put the pad on the wheel, turn the wheel upside down, and get your multimeter out. Do a resistance reading between the spline shaft on the wheel and the back of the horn contact button (the springy thing). It should read an open circuit. When you depress the pad, the meter should read a closed circuit. At least then you'll know if the problem is in the pad.

[andyjboy]

Has your hornpad been dis-assembled at any point ?

It's possible to orientate the parts incorrectly when re-assembling - does the arrowed section line up with the spring-loaded horn contact pin ?




This is the correct orientation of the parts when you turn the hornpad over:

[Silverbullit]

Thanks for the photo Andy...yes, mine is the same. I will test for resistance.
But I may be going backwards....
If the horn contact completes the relay ground, then why when I touch a test light to the contact ring, it's lighted?
Must be the relay???

[Rich Lambert]

You could be picking up voltage through the relay coil which always has (+) power to it, or your relay could be wired wrong. If you run a jumper to ground and touch it to the ring can you hear the relay fire?

[Silverbullit]

You could be picking up voltage through the relay coil which always has (+) power to it, or your relay could be wired wrong. If you run a jumper to ground and touch it to the ring can you hear the relay fire?

Yes, When I tested it this way it energized, and my test light, which was connected to the relay horn output, would blink accordingly.

However, I do have 3 relay terminals hot in static hookup, and pretty sure it should only be 2. I believe I have it correctly wired per research here:

87=double red
86=single red
85=brown
30/51(2) horns

So, pretty sure I need a new relay. Will try that and update. Brian

[Silverbullit]

No new relay yet, but found this contact on back of horn button:

Is there a wire that goes here, perhaps to ground to the steering column housing??

Geez Louise, I can build a 911 motor, can't figure out a 911's horns.