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Discussion Topic:
1939 Horn Operation
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V8JR |
12-19-2012 @ 8:18 PM
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Member
Posts: 95
Joined: Mar 2012
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I am rebuilding my '39 Steering box/column. Can't figure out how the horn will work. The Light Sw rod is inserted into the middle of steering shaft. The horn relay requires a ground to activate the horn relay. It seems that sw rod, which has the horn button incorporated into it, will always be grounded through contact with the steering shaft and steering box making the horn sound all the time. Think this horn button/Lt Sw setup was used 28 through 39. Can anyone shed any light how this system works with out the horn sounding all the time? Jimbo
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ford38v8 |
12-19-2012 @ 9:03 PM
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Senior
Posts: 2758
Joined: Oct 2009
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Jimbo, the grounding wire that activates the relay travels up the horn/light rod to the horn button, which is itself isolated from ground until it is depressed, thereby completing the circuit to ground.
Alan
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V8JR |
12-19-2012 @ 9:49 PM
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Member
Posts: 95
Joined: Mar 2012
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Alan - It seems like the horn/light rod would be in contact with the steering shaft thus making a ground connection since the steering/box shaft is grounded. What am I missing. Thanks for the reply - Jimbo
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ford38v8 |
12-19-2012 @ 10:29 PM
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Posts: 2758
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Jimbo, The wire is insulated, and is connected to the horn button, which does not touch ground until it its depressed. Incidentally, the starter button on your dash board also works that same way, grounding to the dashboard when you push the button.
Alan
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kubes40 |
12-20-2012 @ 6:30 AM
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Posts: 3395
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Jimbo, my guess is you are over thinking this one The horn rod ends within the wiring bale at the end of your steering gear box. Within that bale is a spring loaded terminal, smack dab in the center. The wire from the relay is connected to that spring loaded terminal. When you depress the horn button you are in effect creating the closed circuit (the ground). The rod from the horn button does not touch the steering column tube. Actually the only thing that touches is the back of the button when depressed. That's why it is important to be certain the mating surfaces within the steering wheel hub are free from paint. Guess how I learned that???
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V8JR |
12-20-2012 @ 8:36 PM
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Member
Posts: 95
Joined: Mar 2012
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Thanks so much to all - I have a clearer picture and I probably am "overthinking" this. Did not realize that a wire ran inside the light switch rod - all makes since now - Jimbo
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kubes40 |
12-21-2012 @ 6:20 AM
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Posts: 3395
Joined: Oct 2009
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The wiring does NOT run within the light switch rod. The rod itself acts as the wire.
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40 Coupe |
12-21-2012 @ 7:14 AM
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Posts: 1674
Joined: Oct 2009
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Check the bottom of the rod and you will see an insulator that isolates the insulated horn wire, inside the rod, from ground or contact with the outside of the horn rod, as well as a contact at the very bottom of the insulator. At the top of the rod, under the horn button is another insulator to ensure the insulated wire inside the rod does not touch the rod itself and on top of that insulator is another electrical contact. when the horn button is depressed it touches the top contact sending it to ground potential. Before assembly of the rod place an ohmmeter across the two contacts for continuity and also from one of the contacts to the outside of the rod for isolation from ground.
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MG |
12-21-2012 @ 11:38 AM
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See the horn wire which runs INSIDE the horn rod/tube here: http://macsautoparts.com/early-v8-ford-mercury-horn-rod-wire-repair-kit-4-pieces-ford-a3616rk/camid/F30/cp/JS0R3CHL1074091/
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kubes40 |
12-21-2012 @ 1:42 PM
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Senior
Posts: 3395
Joined: Oct 2009
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see the horn wire which runs INSIDE the horn rod/tube here: What's this have to do with the authentic configuration? Nothing that I can see...
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