Topic: Horn does not work


BRL    -- 10-20-2022 @ 9:20 AM
  Hi Guys:
My car is 1937 Phaeton (model 75-750) and it has the dual horns. One horn does not work and I am wondering if there is any adjustment I can do to make it work. I have taken it off the car and when I wire it directly to the battery it makes a short bleat and I can see the internal parts make a single movement...and then nothing. I see there is a set of points and am wondering if there is an adjustment I can make on these points...anyone knowledgeable about this? See photo of the horn guts. The other horn is a different design with a cover over all the guts so I cant use it as a guide.
Regards,
BRL


fenbach    -- 10-20-2022 @ 8:56 PM
  the points might be stuck together. first, make sure the points open when the internal parts make a single movement. regardless, sand the points with some emery cloth folded in half by slipping it between the points.
the capacitor [the black tube above the coil] is likely bad. try disconnecting it. it protects the points from pitting. if the horn is good but the cap is shorted, the horn will work fine [temporarily] without the cap. you can maybe read the size [capacitance] of the cap on the cardboard sleeve. if not, put in a 0.25 microfarad cap or any condenser from a distributor.
if the horn still doesn't work, you can adjust the point gap by loosening the nut at the end of the bolt and turning the second nut in or out. just remember the original position. the points have to touch when the horn isn't getting power.
honk if it works.


BRL    -- 10-23-2022 @ 9:23 AM
  Hi Guys:
I just received another horn I bought on Ebay because it works and has the correct hardware and OEM wiring. After I tested it, I removed the back cover and noticed that there is a subtle difference between this horn and my horn that doesnt work: my horn has some sort of a round disc with "teeth" on the outside diameter. This disc is mounted on the threaded shaft where the adjustment nuts for the points are located...see previous photo. The new horn does not have this disc...see photo with this message. Is this disc supposed to be there? It looks suspiciously like a disc that may belong in a Klaxon type horn where the disc rotates to activate a diaphragm.

Anyway, thanks to fenbach for the troubleshooting notes...I will try out his suggestions as well as disassemble the horn to see if the diaphragm is intact as well. I will keep you posted on this.



BRL    -- 10-25-2022 @ 9:56 AM
  Hi Guys:
It looks like my horn saga is about over...I have 2 good working horns now, both look OEM, and one is high pitch and the other is low pitch...I am just waiting for some OEM looking pigtails from Sacramento Vintage Ford to wire in and complete the assembly.

Troubleshooting the bad horn: I removed and tested the condenser and it checked good. I removed the diaphragm and resonator and they were in good shape. I repeatedly sanded the points and the horn still would not work with or without the condenser. Then I noticed the points were not square to each other...so I studied the stack up of plates that hold the points and decided to take it all apart and see if maybe I could change the stack up so the points surfaces would be perfectly parallel...I documented the disassembly. I played around with the plates and insulators and came up with a new stack up that allowed the points to be perfectly parallel and the circuit to work like the OEM schematic shows...I reassembled the horn and applied power with a cheap 6V car battery I bought from Autozone...and Voila!...the horn works perfectly and has a high pitch. So someone at sometime had disassembled the points plate stack and re-assembled it incorrectly.

Thanks to advice from Fenbach for troubleshooting. I am somewhat surprised at the lack of part number and mfg marking in all these vintage Ford horns.


BRL    -- 10-31-2022 @ 8:05 AM
  Hi Guys:
Horn saga is over...I installed OEM style pigtails and all the new hardware and so the assembly should look very close to OEM for dual horn (deluxe) assembly for 1937. See attached photos.


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