Yes, another horn thread

[MassMan]

Ok, sorry about starting another "how does the horn work" thread, but all the others don't seem to cover what i'm looking at. I've been poking around the electrical while waiting for some parts to come in to finish my engine, and the horn has me stumped. when i got the truck, both horns were shot. i replaced them with a single $10 unit out of the discount bin. when i tested it, it sounded all scratchy, especially when i wiggled the horn button around. i pulled the horn pad, the three screws, the plastic standoff ring, the thick metal ring, and the thin, convex contact plate. at that point a small pin, plastic retainer and spring shot into my lap. i cleaned all the metal surfaces with emory cloth (all rusty) and applied a little dielectric grease. i replaced the pin/spring/retainer the way the LMC catalog's diagram shows, using a flat screwdriver to push in the retainer and turn it to latch. putting everything back together, the horn didn't work at all.

i've been reading all the horn threads, and people keep talking about wires connecting to the spring or plate or both, but there isn't a wire in sight on mine. i made sure the contact plate is convex out, and makes contact with the center bolt standoff only when pressed, but i have to assume that the contact rod/spring should be pressing against that plate making electrical contact. when i look down the hole where the rod goes, there's a small copper pad set into white plastic at the bottom, and it looks off center, if that helps at all. i've got quite a few pictures, but they need to be re-sized, so i'll try to post the important ones first. thanks for the help.

!!!!!!!!!!!!SOLVED!!!!!!!!!!!!!!!!!
No need for any wires, the LMC catalog's diagram is wrong. See second page of thread.

 

[MassMan]

pics

well, when i try to attach pictures, i get "upload of file failed". i re-sized them to around 69kB but still won't upload. i guess we'll make do without pictures...

 

[K85 Octane]

there is a wire that comes off the plastic thing, that is connected to the upper plate. This wire is essential, I think it's grounded when you push the button. You can see the wire coming through the steering wheel. This wire connects to the horn button assembly.

 

[MassMan]

ok, so there should be a wire. does it connect directly to the convex plate or to the spring/rod somehow? i haven't removed my wheel yet, so maybe this thing is just jammed up inside somewhere. what hole does it come through? it looks like one of the three main screw holes in your picture...

nice dash by the way!

 

[MassMan]

here we go:

the convex plate and what's underneath:


the rod and spring being held in by the plastic retainer:


the retainer taken out:


the rod/spring taken out. the large end of the rod goes in first:


the hole with what appears to be a contact inside:


what bothers me is this all worked before, and there weren't any wires when i opened it up for the first time

 

[K85 Octane]

the wire goes in that hole and is held in place by that "rod and spring". From there it clips onto the top part of the horn button.

See the orangish-red piece at the bottom. That is the top plate for a Grant steering wheel. It has a gold colored tab that the wire gets connected to. Sorry, I have no experience with stock set up.

 

[K85 Octane]

nice dash by the way!

thanks, but I went crazy and started all over again

 

[MassMan]

ah, so the wire goes over the rod. i wonder if an in-line glass fuse holder would work...

 

[mrwilliamsburg33]

I remember taking the assembly apart on an old jeep... I DO know that when you push the horn botton down, you are making the ground connection to make the horn work... Thats what I've read and had experince with. I don't have a working horn on my blazer right now so I'll probably be into this a little later... but I think when you push the exterior horn button, the pin gets pushed down to the contact pad to complete the connection. There should be a ground wire connected to something in that area... not sure as I haven't had mine apart.

Also, about the grease... I'm not sold that that's a great idea. You might be making it worse with all that in there. I personally would just make sure that the contacts are all really clean and wire brushed... then just spray on some WD-40 or some other rust inhibitor to make it better.

 

[euzoa]

I just went through this with my 89. I had gotten the contact kit from lmc as well, but ended up modifying it to replace the little one under the canceling cam (the one that hit you in the face). So I Just ran a wire down into the hole where the contact is supposed to be, pulled it through a little bit so it would stay, and attatched the wire to the back of the horn button. You can also make sure that that is what the problem is by touching a wire from the contact to the center of the steering column (thus completeing the ground circuit). The horn should sound when you do that.

 

[MassMan]

got it!

Well, there's no need for any wires. Everyone that has wires connected has either an aftermarket wheel or a hacked-together horn switch system. Turns out that the diagram in the LMC catalog is wrong. Here's the right way to assemble it (hopefully pictures will come soon):

1 - with the horn button disassembled and the contact rod/spring/retainer removed, insert the spring into the contact hole. it sits against a contact at the bottom of the hole (the one that's off-center in my pictures above).

2 - slip the plastic retainer ring over the contact rod, all the way to the flat base. get some long, thin tweezers and insert them in the two notches in the ring that face away from the flat part of the rod (the tweezers should be parallel with the rod and gripping it firmly.

3 - insert the rod/retainer ring combo into the hole, compressing the spring with the flat end of the rod. rotate the ring to allow its locking tab to slide into the notch in the hole, and then rotate to lock. releasing the assembly, the rod should be sticking out of the hole, and will be spring-loaded, allowing it to press against the convex contact plate.

4 - reassemble, making sure the convex contact plate is facing the right way and is free to pop down onto the rim of the center bolt stand-off.

5 - reconnect the battery, plug the fuse back in, and revel in the throaty sound of your truck's horn (too bad my cheep horn sounds like a compact Japanese car )

i can imagine that the aluminum rod could get worn down after *millions* of horn blasts, but otherwise everything seems to make solid connections.

 

[crazedyak]

Here's my similar situation. I hit the horn, and I heard a clicking under the dash (horn relay), but fail to hear the horn sound. So, I go for the cheapest option, and replace the horn relay. I still hear the relay click, but still unfortunately no horn blaring in my garage.

I have to assume that the Contact Kit is functioning perfectly, because I hear the relay... right? Time to replace the horns?

Thanks for all the above. My inspection is due next month and this is one of those pass/fail criteria.

 

[MassMan]

sounds like either your fuse is blown, there's some cut/grounded/ etc wiring, or your horn's shot. check the fuse first, on mine it's on the bottom right side of the box. if that's not it, disconnect the horn itself and (carefully!) power it directly off the battery (i kept mine grounded, just pulled off the +wire, and tested it with some jumper cables) if your horn works, then you've got a short or broken wire somewhere. the wiring diagram for my 85 shows a fusable link inline with the horn's + wire, so that is also a culprit, though i never came across the link when working on mine. good luck.

 

[crazedyak]

I did some troubleshooting this morning, and got 1 horn working by cleaning all the connections. The 2nd horn (drivers side) only makes a very slight sound if I wiggle it. Pretty sure that it needs replacing, but at least I got one working so hopefully it passes inspection.

Thank you for the assist. Now I get to try to figure out the rest of the problems it has which are mechanical unfortunately.

 

[MassMan]

no problem. it does sound like the horn's dead, that's what mine sounded like when i got my truck. they were full of dried mud and gravel. cleaning them just makes it worse too.

good luck on passing inspection and with all your mechanical issues.