1938 buick horn issue

[Bruce Myers]

My 1938 Buick horn was working fine until I was cleaning the horn ring and the horn went off and would not stop.

I was able to disconnect the wires to the horns after finding a screw driver (about 5 minutes) and they stopped.

The next day my battery was dead as a door nail.  Absolutely nothing.  I recharged the battery last night and the lights worked, blinkers worked with the appropriate voltage drop showing on the dashboard gauge.  No other drop or drain showing on the gauge.  The battery was completely dead again this morning.  It is a fairly new battery.

Any Ideas?

[jvelde]

The horn will only honk when grounded, so I suspect whatever caused it to come on is still grounding the circuit and draining the battery. I would take the horn ring off and see if there is something that has allowed the circuit to complete that needs to be fixed.  There is a foam rubber separator between the horn ring and the horn contact plate that may have broken down.  Bob's Automobilia (www.bobsautomobilia.com) has the parts if this is what you need. Photos in the 1938 Buick Shop Manual are on pages 264-266 (Electrical System Section 12-36 through 12-38).

 

[Bruce Myers]

Thank you

I will check that tonight.

I am surprised that if there is something still grounded that is draining the battery then why does the gauge not show a discharge?

[jvelde]

Well, I do not know why it isn't showing discharge...! Just looked in the Bob's Catalog, and the Horn Button Separator is Part # HS-370 and is listed as $4.25. If you are not familiar with them, they have all sorts of Buick parts.

[Spinneyhill]

It won't show a discharge if the power supply doesn't come through the ammeter. Does your horn take power through the ammeter or just off a terminal that supplies power to the ammeter?

[jvelde]

Bruce,

Welcome to the Forum, always good to have another Pre-War Buick person on board.  I noticed you have posted this in the AACA General Discussion section.  If you scroll on down to the Buick section and post there in the Pre-War Forum, you will get your questions in front of more Buick people familiar with your vehicle - and they are really knowledgeable and helpful.  Post some photos of your car when you get a chance, we love seeing what others have and are working on.

Edited July 11, 2018 by jvelde (see edit history)

[Bruce Myers]

It may be possible that the horn does not go through the ammeter.  Looking at an old fuzzy wiring diagram it is hard to tell.

If the horn wires are disconnected at the horns how is the system draining?  Could there be something in the horn relay switch or is it most likely in the horn button?

[jvelde]

If you disconnected the Battery wire from the Horn Relay to silence the horns, it should not be draining the battery.  If, however you just took the wire off each horn to silence them, the short is still active. The battery connects to the Horn Relay on the middle contact according to the wiring diagram in the Shop Manual.  Still think your issue will be in the horn contact on the steering wheel, since that is where you were cleaning when it started. 

[Bruce Myers]

Thanks

I will disconnect the middle contact on the horn relay until I get the horn button on the steering wheel apart and looked at.

[Spinneyhill]

I recall seeing something in restoration topics here that there is a horn connection part way down the column in the engine bay. Is that the case on your car? Could there be a problem there if it is the case? Or between there and the horn button set-up?

[DonMicheletti]

That sponge rubber part under the horn button can get bad with age. Since it all went south when you were fooling with the horn ring, I expect thet thr rubber insulator is your problem. Cheap fix.

 

As explaine above, it is probable that the relay was activated all the time and thus drained the battery..

 

The horn circuit does not go throught the ammeter, so you wouldnt see the draw

[Bruce Myers]

THANKS ALL.

This site has been a great help.

[jvelde]

Bruce, did you ever figure out what the problem was?  Always good to report the fix for someone else to learn from.

Thanks.

[jp928]

Horns are commonly outside an ammeter due to their fairly high current, and intermittent use. Also they can be accidentally turned on by circuit failures because the horn and the wires from it back to the button are live, just waiting for a ground to occur. I usually fit a relay in a horn circuit so if there is a short the current is low...but fuse that anyway. I was woken once in the middle of the night by the horn sounding in my car parked under the house. Curiously, as I ran down under the house to fix the horn(outside, in bare feet, pyjama pants) I was also surprised by 2 policemen looking for an address further down the street! I wonder what they thought was going on!

jp 26 Rover 9

[Bruce Myers]

Through a process of elimination I determined one of the wires going to the horn relay was shorting out on a nearby piece of metal.