horn wiring. '31

Kube

Kube

Super Moderator
Staff member
I'm thinking it actually makes a difference as to which wire goes where.
Yes? If so, well, which wire goes where?

Thanks fellas!
 
It does not matter because – and I hope I get this explanation right – the horn motor is a commutated series-wound motor. Each wire enters one side of the motor, winds around one half of the stator, and then terminates at a brush which touches one side of the commutator on the armature.

This means that the armature's polarity relative to the stator is always the same. If you reverse the polarity of the current in the wiring (by swapping the leads going into the horn), the polarity of both the stator and the armature will reverse, leaving their magnetic fields in the same orientation relative to each other.

This is why the horn motor rotates in the same direction regardless of the direction of the current passing through it.
 
The different horn manufacturers all used very similar shunt wound motors for better torque. They are not polarity sensitive since it can only turn one direction no matter which way it's connected.
 
Even if the motor did turn the opposite direction (it doesn't) it would not matter as the ratchet will vibrate the diaphragm in either direction.
 
If your horn motor doesn't turn fast enough to OOGAH. The voltage is low. Wire it through a relay direct to battery voltage.
 
oldspert said:
If your horn motor doesn't turn fast enough to OOGAH. The voltage is low. Wire it through a relay direct to battery voltage.
Click to expand...
That might be a bandaid fix when the horn is weak when the engine isn't running. When the engine is running the horn is wired directly from the generator cut out, so it would be getting full voltage from the generator. If it's weak when the engine is off, you have to make sure that all the connections in the circuit are bright and tight! The path to the battery is through the terminal on the cut out, to the junction box, through the ammeter, back to the junction box, to the terminal on the starter switch, to the battery. The path to ground is to the center of the headlight switch, to the horn button, through the steering column, to the frame rail, to the battery.
 
Will N said:
That might be a bandaid fix when the horn is weak when the engine isn't running. When the engine is running the horn is wired directly from the generator cut out, so it would be getting full voltage from the generator. If it's weak when the engine is off, you have to make sure that all the connections in the circuit are bright and tight! The path to the battery is through the terminal on the cut out, to the junction box, through the ammeter, back to the junction box, to the terminal on the starter switch, to the battery. The path to ground is to the center of the headlight switch, to the horn button, through the steering column, to the frame rail, to the battery.
Click to expand...

Worth noting, if anyone is reading this and trying to troubleshoot low voltage at the horn: to diagnose which segment of the wiring has high resistance, you must do your voltmeter check or relay test with a load on the circuit – in other words, while the horn or lights or something that draws real amps is engaged. If you do it with the load off, you'll see 6V across the board.
 
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