test horn

[bigaadams]

odds are you painted the radiator support and if you used a product like POR15 you..the coating is extremely hard and durable and you have lost your ground..the little bit you are getting that has the weak sound is more than not just from a slight bolt contact.  Do remove the horn mount and ensure a good metal to meatl contact (bonding) here..if your horns were working before the odds of them needing adjustment after a bit of body service is extremely remote..you may be able to prove this by using a very good jumper cable from the battery ground straight to the horn...must be heavy guage wire and good contact...

[PlymouthSpDelux]

I adjusted the horn and gave it a better ground, but it made no difference.  Then I gave the spare horn a better ground and it worked!  I switched the guts out of the spare horn and put them in the other one, so I would not have to paint the spare to match what's already in the car.  It was after midnight by the time I got all that done.  I was counting on the neighbors being in a deep sleep when I gave it the test beep!   ::)

[36 Ply]

Plymouths & Tod Fitch have both given good advice concerning testing horns. And you shouldn't hate to ask any question; I believe that is one of the main reasons that this forum exists, to share information.

I have both asked for and given advice on this forum; I really doubt that anyone knows everything about everything, but the cool thing is that what you or I don't know, someone else does.

Good luck with your horn.

Regards,
Pat O'Connor

[PlymouthSpDelux]

These are also high current devices and need a really good ground. Is there some way that the ground to the horns was affected when you did your radiator work?

Thank both of you for your advice (Plymouths & TodFitch).  I'll have to fuss with the adjusting screw tomorrow, but it would be odd if it changed adjustment under the cap, which I never removed until today.  Anything is worth a try.  TodFitch's comment made me remember something I had forgotten about.  When I installed the radiator for the second time, I had to remove the long horn (only the long horn, which is the one that is not working now) to get access to a stubborn petcock valve.  Perhaps I somehow altered the ground during that process?   

[TodFitch]

These are also high current devices and need a really good ground. Is there some way that the ground to the horns was affected when you did your radiator work?

[FourDoor]

Usually when you are testing a horn and it just goes 'click' it's because it's out of adjustment. Most,if not all, those old horns had an adjustment screw sitting over the relay arm,this is the vibrating relay inside the horn, that has to be turned back and forth to find the most reliable point for 'noise' startup. But how would your horn get out of adjustment?? Anyways it may be just as easy as turning the screw while applying power. The adjustment screw usually has a locking nut on it that has to loosened first and then tightened down after adjusting. Cleaning the points with some emery cloth on the vibrating relay may be in order too.   

[PlymouthSpDelux]

I hate to ask this because it will show how stupid I am when it comes to electricity.  For the sake of my Plymouth, I need to swallow my pride and post! 

The trumpet horns on my '48 have worked forever.  This winter I cleaned the engine compartment, including pulling the horns out.  They continued to work fine after I reinstalled them.  I had to pull the radiator a second time because of a small leak.  After installing the radiator again, only one horn worked.  I never touched the wiring during the radiator's second removal.  I have no recollection of damaging any of the wiring or the relay, and it looks fine. 

I got another relay and still only one horn works.  I took the wire off the working horn and put it on the other one.  While there was an audible "click", it still did not blast any noise.  I even have a spare set of horns, but do not know if they work.  I used the wire from the relay that went to the non-working horn on the spare horn and it was dead too.  I took the top off the non-working horn and it looks fine with no breaks in the wiring.

I am sure there's some kind of test I could do on the horn, but I don't know what test to do or how to do it.  I would suspect the wire, but while it is old and original, it is solid and does not look any different then before when everything was working fine.  It does not have any frayed bare exposed wire.  Anybody know what's going on here, or how to test if the horn is dead?  Thanks in advance.