The Stovebolt Site Forums The Shop Area The Electrical Bay Horn wiring question

Hey guys. I rarely post, but read here a lot. Lots of good info. My 47 Loadmaster 2 Ton truck is getting close to road ready. My goal is to paint this summer and get it all put back together. For now, it runs, drives and stops. Just some body work and electrical stuff left. Got the taillights (it has a dump bed w/no lights) and brake lights working. Have an old Yankee 960 signal, but from what i can, its tough to get that thing to do what i want...so i ordered an aftermarket signal switch. Messing with the horn now. The horn itself (trumpet style with 2 terminals) works. I can put 12v to one side and ground the other and the horn sounds. I've got hot to my horn terminal on the fuse block. My issue is on the steering wheel. On the opposite side of my fuse block, I can get continuity from there all the way back to where the wire goes into the steering column. I pulled all I could off the steering wheel...cap, contact plate and the pin. I now see nothing on the wheel besides the stud that the wheel is pressed to and then there's what I assumed should be the other end of the wire. it's a white round thing with a lead contact in the middle. I was hoping I would get continuity from the wire entering the steering column to the lead contact but I get nothing. Is that actually where that wire connects to? I don't have a wheel puller but think I may have to find one. Appreciate the help.

That white round thing that you removed from the hub is the Horn Contact Spring and Bushing. That contacts the Steering Column Upper Bearing. The wire that is exiting the steering column is connected to that upper bearing. You should have continuity between the face of the bearing that you can see thru the hole in the wheel hub and that loose wire exiting the steering wheel. You may have to pull the wheel to get access to clean the face of the bearing where the Horn Contact Spring rides.

Thanks for the reply. I removed the small white contact pin but hopefully you can see the pic. Am I understanding that I should have continuity from this contact shown to the wire in the column?

Yes that is correct. Remove the contact pin and see if you have continuity to the ring under the steering wheel hub.

The Contact Spring and Bushing has a spring inside. Looking at your picture it appears that the contact is depressed just below the top of the bushing and has no spring left to it. It may just be sticky but needs to stick up a bit to touch the contact plate.

[img]https://www.stovebolt.com/ubbthread...1303A39-F6F1-47B0-ABDC-5FBC5B6D5B13.jpeg[/img]I removed the steering wheel to access the instruments. I temporarily replaced the wheel but now the horne doesn’t blow. I have continuity from the pin to the relay & I have 12 volts.
The contact bushing has very little and only one place continuity.
It must be bad.
How can I toot my horn without the contact spring in place. The pin is in the wheel.
Thanks

Since your horn plate lacks a locator tag (a bent piece of metal which engages and properly locates the plate to the steering wheel), you need to ensure that you avoid placing the plate onto the spring loaded contact brush in such a manner that it lands on one of 3 insulted rivets on the contact plate.

In the picture above, If I check continuity from the black bracket (which when pushed against the plate with the 3 insulated rivets) there is no continuity. I think that pushing them together would make contact with each other, resulting in the horn blowing when in the steering wheel?
The horn does not blow at all now. Without the spring plate in place can I toot the horn with the pin? I guess I am confused on how/ what makes the horn toot! The relay is hooked up, I have 12 volts to it and the pin has continuity to the bearing and wire and the horn is connected.
Oh, it is new, this is how it came to me.

In my house and re checking for continuity, the back plate seems to make continuity with the black bracket when I push the black bracket together with the back plate (the back plate has the 3 insulated rivets. Those rivets go in the wheel first, then tighten the nut down on the wheel. The horn should toot when pressed??
Thanks,

The silver plate on the Horn Button Retainer (the part in your picture) makes contact with the Contact Spring and Bushing which goes thru the hub of the wheel and makes contact with the Upper Steering Column Bearing providing 360 degree continuity thru the steering wheel even when turning. The black part of the Horn Button Retainer is held in place by the nut holding the wheel on and provides the ground. The insulators (3) on the Horn Button Retainer keep the two plates from contacting while the button is at rest. Once you depress the Horn Button, the black and silver contact one another and provide the path to ground.

You should be able to sound the horn by taking a wire, stripped on both ends, holding one end to the steering shaft and the other end to the Contact Spring and Bushing.

Thank you P !

P, I had the 25 amp fuse burned?😄

Good to hear! Glad you figured it out.

Thanks for the help Phak. The little pin I removed was part of the contact plate that was broken. I pulled the pin spring and it’s broke. I ordered the new parts I need. I was able to get continuity through the column so hopefully once the parts are here I’ll be good. Appreciate it

Your welcome! We all love to hear success stories on this forum!

This is all new to me so I’m learning as I go. It’s been quite and experience so far but guys like you really help out.

Sorry to bring this up but I can’t get it going. Hoping for some more help. Dumb on my part but I didn’t take a pic when I took it apart. Anyone have a diagram of how it all goes back together? The first plate has a little alignment pin that I assume goes into a small hole on the wheel. But that doesn’t seat flat. I put that in then the contact plate and small washer then the nut. I may have over tightened as I bent that first plate up a bit. And the horn didn’t work. Does the spring in the bushing provide the connection between the 2 contact pins. It seemed to work for a second but almost welded the spring to itself as it completely collapsed. I know I’m asking a lot of different things here. Ideas?

Yes, the spring pushes the two contact points out so they make the electrical connection between the upper steering bushing and the horn button retainer plate. You can buy a replacement at Classic Parts