71 Demon - ALL new wiring; under dash, column, engine etc and NOS horn relay.

Horns had been working - Prestolite pair that I had the powder coater PAINT and not powder coat due to the heat.

Horns stopped working, checked fuses - all good.

Standard base steering wheel - push the button and you can hear the relay "click".
Took horn pad off and took the column connector off the steering wheel switch and grounded to the center nut, same thing relay just clicks.

Bought new relay - same thing just clicks.

Then ran piece of 14GA wire from the + post and touched it at the post and the terminal on each horn, nada.
Removed the horns from the brackets and laid them one at a time over the - battery post and touched the wire from the + post to the horn terminal and nada.

I did screw in/unscrew the adjuster screw on the front of the horn and same thing.

Could BOTH horns have gone bad? or am I missing something?



TIA

Seems to me that if the horn is grounded and you touch the Positive terminal with a 12V jumper wire the horn should sound.

agreed

Rico , check the ground connection , your powdercoat could be the issue

Check them for continuity with any multimeter.
Simple inside: a coil & set of contacts.

Ok, hooked test light to each of the plugs and had my son press the horn button, each horn press resulted in the test light illuminating. So it appears power is getting to the plugs, so must be grounding or the horns are bad?

The horn brackets are powder coated so perhaps I should lightly sand the contact area with the horns and also where it contacts the rad support?
But as I stated i ran a power wire to each horn and nada?

So it seems a light coat of paint on the contacts from the painting process might be the issue (?).
I hope you don't have to do it, but: https://wichargerguy.proboards.com/thread/18732/rebuild-restore-horns

Horns should ground through the attaching bolts; if those threads are clean, should have ground.
I have had a dead horn, but I can't recall which vehicle...I've owned over 90 so far.
I've also had 1 Mopar that needed the steering wheel in certain positions for the horn to work, but that doesn't sound like the issue here.

It helps to have a toothed washer between the bolt and horn for a good ground through the bolt.

I have been able to revive many over the years flushing with carb cleaner / brake clean and air. If the openings were not blocked prior to blasting /painting etc. there's a good chance they are full of debris. Pouring or spraying the chemical in, block the opening and roll the horn to get the liquid into the center. Repeat until you can hear the liquid inside the horn when you shake it.
Reverse and see how much cr-p comes out.
Repeat above if needed.
Counting the number of turns, Remove the adjusting screw, write the number down.. If it is dry, it's sealed. Squirt the cleaner trough the hole and shake. Repeat as needed.

Flush both sides with air and set aside in a warm area to evaporate any remaining solvents.
When no residual vapors are detected, Reinstall the screw the same number of turns.

Bench test. Sometimes adjusting the screw under power will wake them up.
The above method has worked many times but not always. Probably ` 75%|
If this does not work refer to the article suggested.
You decide which is easier

Not to hijack the thread but has anyone ever found a source for socket used to turn the adjusting screw???

exactly , the original bolts that hold the horn , and other electrical components throughout the car , sometimes have toothed washers that will dig into the thin paint on the part . This is how they get their ground instead of using a seperate wire , the washer digging into the paint combined with the bare threaded hole that the bolt screws into makes the ground connection.

With the practice of over restoration that is prevalent in the hobby many parts of the body get painted that were never originally painted, in combination of over restoring parts that get bolted on .,. kinda like powder coating a horn ..... can create electrical issues ...

Can both horns be bad? Sure, both are the same age, had the same use and were subjected to the same environment. It would make sense if they both failed at eh same time.

In your case though, I suspect a bad ground like many others pointed out.

don't forget, there is no power going through the steering wheel switch. when pressing the horn button, it GROUNDS the wiring going to the relay, [through the wheel and column. don't forget the column ground strap or wire] thus energizing the relay sending 12v to the horn, which needs to be properly GROUNDED to sound.

Thanks everyone for the great suggestions!

Will try getting the insides cleaned out as suggested.


Mopar buddy about 20 mins away has a horn possibly two that are known to work. Gonna borrow and see what happens.
I cleaned the brackets with a dremel (mounting area) as well as cleaned up the mounting area on the rad support and still nothing. Leaning heavily towards the horns are bad. We'll see once I get the loaners.

Keep us posted. I am curious.

I have brought some horns back from the dead by spraying a good amount of WD-40 into the mouth of the horn and then rotating it so that the puddle follows the spiral to the center. Then I let it sit awhile. Then I reverse the process to get as much WD-40 out as I can before applying 12v. If that doesn't work I give the horn a few LIGHT taps with a hammer to see if I can free the diaphragm.

I don't recommend buying old horns from eBay unless the seller says explicitly that they work. Lots of dead horns on eBay.

I have applied power and ground to a horn and then tapped on it to get it working. Something about the points inside sticking.

This was great advice!

First; THANK YOU to everyone that took time to help diagnose this issue. Been away for a few days for baseball and wanted to report back.

While working with these horns, accidently dropped one on the garage floor and when I picked it up, there was a chunk of crud on the floor. Shook the horn and sure enough it had a bunch of media that had hardened from when it was blasted prior to painting. Same with the second horn when I gave it a whack with a soft mallet. Even after that, still no "honk" after blowing compressed air in it and through the adjuster screw hole and bolting up with the cleaned up mounting brackets.

Lastly, borrowed a set of working Sparton horns from Mopar buddy and that did the trick. Soon as they were bolted up, they worked flawlessly. After that bought new set of Sparton horns and bolted those up and same thing, working flawlessly! BUT, after getting both sets of horns bolted up, came to realize that one of the original horns was not working to start. It was nowhere as loud as it is now with working horns. So, I was only working with one working horn to start and then that one gave up the ghost. ** We did try jumping the old horns once again after the media was discovered inside them and they just will not work.

Thanks again for all the good advice and diagnosing techniques, it was all very much appreciated!!
1971 GY3 340 Demon

thanks for the update

X2

Isn’t the primary use of an auto horn to calibrate the free Apple app NIOSH Sound Meter?
Or does everyone use the $7 “Storm Whistle”.

Don’t forget standing by the railroad tracks to pick up the 130 db locomotive horn when it blows.

Only “weirdos” fail to consider such matters.....