GRRRRR!!! Horn not working!!!

[HIGHWAY BY THE SEA]

This week my NOS GMC horn button arrived in the mail from the dealership, and the spring disc from a VERY helpful board member. When I installed everything in the 67 3500, the horn did not work (I was not surprised).
So I removed the horn button and fooled around with the assembly. When I touched any of the horn screws with a screwdriver and the horn cup together, the horn would honk, but not with the button pressed. The relay would also click like it is supposed to.
So I disassembled all of it and cleaned everything, then reassembled it again. Now not only would the button STILL not activate the horn, the screwdriver/screws trick no longer did either. The relay no longer clicked either. I went through the assembly multiple times but found nothing wrong. I even cleaned/buffed the steering wheel under the disc to ensure good contact and ensured it was not pinched. I also checked the fuses. And I recently replaced the turn signal switch with a brand new AC Delco one.
This morning I bought a new horn relay and installed it, but...you guessed it...NO HORN!!!!
I went though dozens of horn threads, but NOTHING that I tried worked. Anything I may have overlooked? And why would cleaning the horn assembly cause to stop "jump" honking?

[Andy4639]

Lets see what you got man. Post some pictures.
The 67 has the cup and it should have the plastic under it plus the spring washer plate.


See if this helps.

You Tube

[HIGHWAY BY THE SEA]

Here is what I have (not all pictured). The horn has been tested, and works. I have: cup, plastic tri-gasket, spring disc, rubber horn button gasket, NOS horn button, three screws, and canceling cam.






HELP!!!

P.S. That Youtube video is not loading...?

[Andy4639]

Give it a few seconds. It's working for me.

If it doesn't go to you tube and type in 67 truck horn button install.

[LockDoc]

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That video is kind of messed up. There is no way it can work with the thin plastic disks he made and put in there. That's why he can't get it to work.

The disk is the first piece to go inside the steering wheel (dome side up) then the metal cup, then the plastic retainer with the three screws. If you hold the metal cup in your hand and put the retainer down inside it you will see that the bosses on the plastic retainer fit snug inside the holes in the cup. Turn that assembly upside down and put the metal disk on it and you will see that the holes in the disk just fit over the bosses on the retainer also. That is the way it has to go together. It can be tough getting it all lined up down inside the steering wheel and keeping the metal disk in place. If the disk gets out of place and gets pinched between the steering wheel hub and the retainer, either the horn won't honk or it will honk all the time.

You may have to take a small screwdriver and push the metal disk up from the bottom after you have the screws snugged up to get it in place. When you have all of the parts installed and you push on the edge of the metal cup it should push down a little bit, it should not be solid. If it is solid or the horn honks when you hook the battery back up the studs are on the disk and not through it.

As far as the relay not clicking hook a ground wire with alligator clips to bare metal on or under the dash and touch the pin and see what it does. You may have to pull the cancelling cam out and touch the pin under it.

LockDoc

[Andy4639]

Originally Posted by LockDoc

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That video is kind of messed up. There is no way it can work with the thin plastic disks he made and put in there. That's why he can't get it to work.

The disk is the first piece to go inside the steering wheel(dome side up) then the metal cup, then the plastic retainer with the three screws. If you hold the metal cup in your hand and put the retainer down inside it you will see that the bosses on the plastic retainer fit snug inside the holes in the cup. Turn that assembly upside down and put the metal disk on it and you will see that the holes in the disk just fit over the bosses on the retainer also. That is the way it has to go together. It can be tough getting it all lined up down inside the steering wheel and keeping the metal disk in place. If the disk gets out of place and gets pinched between the steering wheel hub and the retainer, either the horn won't honk or it will honk all the time.

You may have to take a small screwdriver and push the metal disk up from the bottom after you have the screws snugged up to get it in place. When you have all of the parts installed and you push on the edge of the metal cup it should push down a little bit, it should not be solid. If it is solid or the horn honks when you hook the battery back up the studs are on the disk and not through it.

As far as the relay not clicking hook a ground wire with alligator clips to bare metal on or under the dash and touch the pin and see what it does. You may have to pull the cancelling cam out and touch the pin under it.

LockDoc

I was thinking the same thing on those plastic sheets. I've never seen anyone use them before. But I haven't seen everything!

[dmjlambert]

Cart before the horse. There is no point worrying about the cup and spring in the steering wheel before knowing that the relay and wiring works with the horn and knowing the internal wiring of the column and the relay will honk the horn.



With the steering wheel off and you short A to B in this photo, does the relay click and horn honk? If not, fix that situation first before moving on to the steering wheel and horn button assembly.

[HIGHWAY BY THE SEA]

OK, removed the steering wheel and canceling cam today. Grounded the turn signal springy-rod thing to the steering wheel shaft. I did this with it both pushed in, and sticking out. NOTHING. So this is not the problem. But remember, it DID previously "jump honk" with a screwdriver touching the horn cup and screws simultaneously before I cleaned those parts. I must have shorted something out somewhere, but I cannot imagine what it could be. I also "battery honked" the horn with a jumper wire just to be sure the horn had not blown out. Next step...?

[Andy4639]

Next step is to find where the path is broke. I would start at the connector under the dash going to the column.

[HIGHWAY BY THE SEA]

I traced the wiring and found that the new horn relay was not plugged in quite enough (bright flashlights under dark dashes do wonders with my 49 year old eyes) so I corrected that. So I repeated my last grounding test with the steering column rod, and springy rod thing, and the horn works when I do that. So I reinstalled the steering wheel, and all the horn parts in the proper manner, but STILL no horn!!! Horn problems seem to run RAMPANT with these 67 - 72 trucks, and I wish that I could force GM Motors to issue a long-overdue recall on these things!!
Horns are required to make vehicles street-legal in this state, and I am about ready to throw in the towel on this!!!

[71gmcC15]

I have a 71 gmc with a 67 gmc steering wheel and horn asembly and it works great. My horn is from a 94 chevy. So the plug was changed. Maby the horn is not getting a good ground. When you put it all back together and tryed it did the relay click? If so them maby it's the horn ground. I know the original horn grounded its self but maby. Just a gess.

[dmjlambert]

Originally Posted by HIGHWAY BY THE SEA

... I corrected that. So I repeated my last grounding test with the steering column rod, and springy rod thing, and the horn works when I do that. So I reinstalled the steering wheel, and all the horn parts in the proper manner, but STILL no horn!!! ...

OK so now you know the problem is definitely not in the steering column or in any part forward of that, because your relay and horn work, and the wiring up the column works. The problem is limited to the last few parts that mount on the steering column. Take those apart and put together more slowly. Tell us the first point at which it does not work, and don't put it together beyond that point without correcting the problem.

First the cancelling cam that has the tower and spring loaded pin.



Slip that onto the steering column, move it around, and make sure when you short its pin to the steering column shaft the horn honks. Then put the steering wheel on, and repeat. Make sure when you short the cam's pin that is sticking up through the steering wheel, to the steering column shaft, the horn honks. Then put the convex spring into the steering wheel recessed cup, so it rests on the plastic of the steering wheel hub and is in constant contact with the cam's pin.



Push down on it and confirm it snaps down against the center metal part of the steering wheel where the steering column shaft sticks through. When it snaps down like that, the horn should honk.

Next put the cup and spacer on with screws.



Press down on any part of the cup and it should honk the horn. These are pictures of pieces LockDoc posted in another thread.

[Andy4639]

Originally Posted by HIGHWAY BY THE SEA

I traced the wiring and found that the new horn relay was not plugged in quite enough (bright flashlights under dark dashes do wonders with my 49 year old eyes) so I corrected that. So I repeated my last grounding test with the steering column rod, and springy rod thing, and the horn works when I do that. So I reinstalled the steering wheel, and all the horn parts in the proper manner, but STILL no horn!!! Horn problems seem to run RAMPANT with these 67 - 72 trucks, and I wish that I could force GM Motors to issue a long-overdue recall on these things!!
Horns are required to make vehicles street-legal in this state, and I am about ready to throw in the towel on this!!!

Ok you got the horn to work by shorting it to the shaft right but not with the horn itself.
Take it back apart and start over and check out my pictures I posted to make sure the parts are right. Installed correctley.

[dmjlambert]

Just to give you an idea of how this method can help, my horn quit working a few months ago, and I found after doing this troubleshooting that a little bit of dirt and corrosion under the spring inside the cancelling cam prevented the horn from honking. I took the pin, retainer, and spring apart from the cancelling cam, and used a Q-tip with some Brasso cleaner to clean up and shine the metal at the bottom of the cancelling cam's tower. Cleaned up the spring and pin as well. Problem was solved. You may have something else wrong, but you can find out what is wrong by assembling slowly and testing at each part added.

That video Andy4639 posted is from another forum member nickmomrik, who found that his horn cap did not have enough clearance to move down far enough, so that is what the additional homemade plastic spacers fixed.

It helped me recently as well!

[dmjlambert]

The plunger does not need to go down and make contact with that metal ring. The spring is what conducts. The electricity flows from the spring plunger that sticks up out of the column to make contact with the cancelling cam round plate, then from the top side of the cancelling came it goes through the spring you show a picture of, then through the plunger, then to the convex spring plate that is part of the horn button assembly. All of those parts should be in constant contact with each other. Then, if the convex spring comes into contact with the center hub of the steering wheel to ground it, the circuit is complete and horn honks.

I had my horn stop working once and took the cancelling cam spring and plunger apart, although I didn't take the large metal ring off the plastic like you did. I didn't know that part came off. I cleaned up the spring and plunger and cleaned the bottom of the tower hole to make sure it was clean bare metal. That fixed it for me. I used some brasso metal polish on a q-tip.

[HIGHWAY BY THE SEA]

Well, the horn is finally fixed! It was in fact the plunger spring in the canceling cam. After I took it apart, I used a Scotch Brite pad to clean where the spring touches the brass on it. Even thought it did not appear dirty, this somehow fixed the problem. What makes this so odd is that the old canceling cam that I removed from this truck did not work with the horn either. Weird.

[Getter-Done]

Glad to hear you got it fixed.










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[Andy4639]

Good to hear it!

[DennisP]

Not bad! Only took you a year!

[HIGHWAY BY THE SEA]

Originally Posted by DennisP

Not bad! Only took you a year!

Yep! I put the horn on the back burner until I was able to get other issues fixed first!

Now on to the wiper motor...

[cdk]

With the info from this thread ,I got my horn honking! Thanks for the post !

[dmjlambert]

You're now a horn honker! Welcome to the forum. If you want to start a new thread and post your truck story and/or pictures you'll get all sorts of folks greeting you and giving you encouragement (if you need it). We like pictures. The manage attachments button is what you use to upload pictures.