Horn only works while driving

[sconnors]

The previous owner put a horn button in the car and it’s mounted to the steering column. The horn works fine as long as I’m driving but sitting still in traffic with the car running or just turning the key on it doesn’t blow.
Any ideas?

[Marshall V. Daut]

The horn needs oiling in its two felt pads. Also, back the adjusting screw out one or two clicks to allow the armature to spin easier. Readjust after oiling.

The reason the horn only works when driving is because your generator is putting out more juice at speed than when idling. The extra juice is enough to overcome a dry armature shaft to make the horn's armature spin. This is indicative of an armature that needs oiling and perhaps the commutator plates sanded with 220 wet-dry sandpaper.
Marshall

[Y-Blockhead]

I recently attended a most excellent "Honk Your Horn" seminar at CCRG Bakersfield and one of the topics was oiling your horn and cleaning the comutator. Good info.

[Jim/GA]

On a horn that is kind of old, it is worth opening up the diaphragm behind the horn bell to inspect for wear on the diaphragm "button' and the rotating piece on the shaft. If they are rough, they don't sound so good.

They are quite easy to replace if worn. While it is all opened up, whether you keep the old parts or install new ones, put a light smear of grease on the rotating piece for a better sound.

[Joe K]

And, one thinks of the "ground" which while the car is "vibrating" probably makes a momentary ground good enough to sound the horn. While stationary maybe not so much.

Most horns have a single wire "feed" with the ground being made through the headlight bar. The usual issues with the headlight bar is "paint" - which gets in the way of both horn and headlight grounding. For the headlights the problem is worse simply because of more joints/paint layers.

But the horn may have its own affectation separate from the lighting.

Joe K

[Werner]

Sponsored Links (Register now to hide all advertisements)

Sconnors,

I can certainly confirm what was written previously. I personally wired a relay in between to minimize electrical resistance. The correct adjustment of the pressure screw is also important.

[Keith True]

Is it an original 2 wire horn,with one wire that grounds through the horn button,or is it an old single wire,that grounds through the headlight bar and the brackets.Lots of those single wire horns still around,they were sold by the thousands in the 50's,60'sand 70's.

[nkaminar]

Also helps to adjust it.

[mcgarrett]

When mine hesitates to respond like it should I have to remind myself, it's a 96 year old 6 volt electric motor hanging out front in the wind, rain, and the elements with nothing to protect it from any of that. What could go wrong??

[Marshall V. Daut]

Another thing I have noticed from car to car is if the horn unexpectedly fails to honk, try rotating the horn button in the center of steering wheel a few degrees one way or another. Rust and corrosion sneak in underneath the button and can interrupt the circuit closing action of the metal-to-metal parts that sends electricity to the horn. Sometimes you can rapidly twist the horn button back and forth to scrape away a bit of this crud and make the button functional again - for a while. Try moving the button a little left or right and see if that helps should the horn operation become intermittent. I still say, however, you can't beat oiling the felt armature shaft pads and fiddling with the adjusting screw. Those are the first and easiest steps to take before calling in the Marines.

Here's another simple check you can make. The OP states that the horn won't honk at idle, but will do so when driving. O.K. While the engine is idling, rev up the engine and try honking the horn. If the added juice makes the horn now work, my money's on dry armature shaft felts, followed by an adjustment.
Marshall

[Y-Blockhead]

Originally Posted by Joe K

And, one thinks of the "ground" which while the car is "vibrating" probably makes a momentary ground good enough to sound the horn. While stationary maybe not so much.

Most horns have a single wire "feed" with the ground being made through the headlight bar. The usual issues with the headlight bar is "paint" - which gets in the way of both horn and headlight grounding. For the headlights the problem is worse simply because of more joints/paint layers.

But the horn may have its own affectation separate from the lighting.

Joe K

The horn itself is not grounded. The ground is thru the horn button. When you press the button, it completes the circuit.

[sconnors]

Originally Posted by Keith True

Is it an original 2 wire horn,with one wire that grounds through the horn button,or is it an old single wire,that grounds through the headlight bar and the brackets.Lots of those single wire horns still around,they were sold by the thousands in the 50's,60'sand 70's.

Mine has two wires

[sconnors]

Originally Posted by Marshall V. Daut

Another thing I have noticed from car to car is if the horn unexpectedly fails to honk, try rotating the horn button in the center of steering wheel a few degrees one way or another. Rust and corrosion sneak in underneath the button and can interrupt the circuit closing action of the metal-to-metal parts that sends electricity to the horn. Sometimes you can rapidly twist the horn button back and forth to scrape away a bit of this crud and make the button functional again - for a while. Try moving the button a little left or right and see if that helps should the horn operation become intermittent. I still say, however, you can't beat oiling the felt armature shaft pads and fiddling with the adjusting screw. Those are the first and easiest steps to take before calling in the Marines.

Here's another simple check you can make. The OP states that the horn won't honk at idle, but will do so when driving. O.K. While the engine is idling, rev up the engine and try honking the horn. If the added juice makes the horn now work, my money's on dry armature shaft felts, followed by an adjustment.
Marshall

When at idle, if I rev the engine the horn still does not honk. It only honks when I'm driving

[Joe K]

Originally Posted by Y-Blockhead

The horn itself is not grounded. The ground is thru the horn button. When you press the button, it completes the circuit.

Thank you - a worthy reminder. And in this case grounds through the "added pushbutton" - which may have its own grounding question.

I wonder how many dashboards have been drilled to add the pushbutton - kind of a physical acknowledgement of the fail of Ford's original design.

But we're talking generational time here.


Joe K

[Marshall V. Daut]

"When at idle, if I rev the engine the horn still does not honk. It only honks when I'm driving"

Interesting. Possibly the vibrations from the road shake the horn up enough to get the armature to turn, kind of shocking it into action. Please let all of us "horny" guys know what the problem was after you have solved it. The answer lies in one of the postings so far. That the horn works at all is a big positive.
Marshall

[sconnors]

Here’s n update: Oiled the felt pads although they seemed well oiled, used some fine sand paper to sand the copper contacts and other part and the turned the adjustment screw back one full turn, and the horn spun but didn’t honk, turned the screw back one full turn to the original position and it honked fine! Seems to be fixed.

[Y-Blockhead]

Originally Posted by sconnors

Here’s n update: Oiled the felt pads although they seemed well oiled, used some fine sand paper to sand the copper contacts and other part and the turned the adjustment screw back one full turn, and the horn spun but didn’t honk, turned the screw back one full turn to the original position and it honked fine! Seems to be fixed.

Nice going, thanks for letting us know.

[rotorwrench]

The light switch/horn rod can be repaired to do away with the band aid column button. The wire inside and the lower end terminal can get deteriorated but that stuff is in the available kits to repair them. The power wire comes direct from the generator so as to be as short as possible. Resistance is not your friend with a 6-volt system. Deteriorated wire and loose connections make for more resistance which robs the little motor of potential full electrical power in the circuit. The starter motor has big cables to deliver enough current for it. The horn is the next highest current draw in the whole electrical system even though both are considered intermittent circuits. The lighting system is a close 3rd but it is a continuous circuit when driving at night.

The model A electrical system is just barely able to keep up with general driving needs. If driving at night a lot, it was recommended to increase the charging current to keep up. Most folks were too lazy to mess with stuff like that so they would drive until the lights started to dim and just hope they made it home. Setting the charging current output too high could boil the water out of the battery quicker and reduce it's service life. Ford used this system till the 1939 deluxe model cars and longer in tractors but there were two stage current relays available for the generators after the change to the model B set up. These units could fail and leave a person stranded so you don't see too many of them around anymore. It was more of an oval shaped unit than the conventional generator cut out.