How to check a horn button

[1955fle]

My trumpet horn on my '55 FL stopped working. I believe the horn power pack is OK. Is there a way to check the horn button to see if it is function properly.

Carl

[Mongrel505558]

The handlebar switch grounds out the horn. If you disconnect the wire from the switch to the horn and leave the wire grounding the switch you can check for continuity between the switch wire meant for the horn and ground when you press the button.

[1955fle]

The handlebar switch grounds out the horn. If you disconnect the wire from the switch to the horn and leave the wire grounding the switch you can check for continuity between the switch wire meant for the horn and ground when you press the button.

Thanks for the advice. I will try and check the button.

Carl

[Mongrel505558]

Do you have the factory wiring diagram? If not, you can find it in the "Downloads" section of this site. I'm using the single-wire horn button that just grounds to the handlebar when you press it, but the two-wire button also grounds out the horn. The ground wire from the horn attaches to a terminal board mounting screw, I believe. Usually a circuit is arranged with battery to switch to device to ground, but the horn, and also the single terminal neutral light switch, are arranged battery to device (horn or neutral indicator bulb) to switch to ground. It really doesn't make any difference electrically, but you have to be careful when wiring to dash light sockets. Some are isolated and some are grounded at the dash.

The first thing you should do is make sure your horn is actually getting +12V from the ignition switch. Take a wire and go from the battery directly to the horn's hot terminal (the one that doesn't go to the pushbutton). Then proceed with the testing.

When you disconnect the horn to button wire the simplest thing is to take that wire and ground it directly (touch it to the crankcase or head or any other bare metal that's well grounded). If the ignition is turned on that should sound the horn if your horn power pack is okay. If it doesn't then check the button.

[PanPal]

I believe the horn will sound with the ignition switch on or off. My 59 did.

[1955fle]

Do you have the factory wiring diagram? If not, you can find it in the "Downloads" section of this site. I'm using the single-wire horn button that just grounds to the handlebar when you press it, but the two-wire button also grounds out the horn. The ground wire from the horn attaches to a terminal board mounting screw, I believe. Usually a circuit is arranged with battery to switch to device to ground, but the horn, and also the single terminal neutral light switch, are arranged battery to device (horn or neutral indicator bulb) to switch to ground. It really doesn't make any difference electrically, but you have to be careful when wiring to dash light sockets. Some are isolated and some are grounded at the dash.

The first thing you should do is make sure your horn is actually getting +12V from the ignition switch. Take a wire and go from the battery directly to the horn's hot terminal (the one that doesn't go to the pushbutton). Then proceed with the testing.

When you disconnect the horn to button wire the simplest thing is to take that wire and ground it directly (touch it to the crankcase or head or any other bare metal that's well grounded). If the ignition is turned on that should sound the horn if your horn power pack is okay. If it doesn't then check the button.

I have a single wire horn button. I took the horn apart and took some measurement based on a instruction sheet I downloaded. The horn seems to do what it should. I have not run a wire from the battery to see if the horn is working that will be my next step.

Carl

[Mongrel505558]

Do you have the factory wiring diagram? If not, you can find it in the "Downloads" section of this site. I'm using the single-wire horn button that just grounds to the handlebar when you press it, but the two-wire button also grounds out the horn. The ground wire from the horn attaches to a terminal board mounting screw, I believe. Usually a circuit is arranged with battery to switch to device to ground, but the horn, and also the single terminal neutral light switch, are arranged battery to device (horn or neutral indicator bulb) to switch to ground. It really doesn't make any difference electrically, but you have to be careful when wiring to dash light sockets. Some are isolated and some are grounded at the dash.

The first thing you should do is make sure your horn is actually getting +12V from the ignition switch. Take a wire and go from the battery directly to the horn's hot terminal (the one that doesn't go to the pushbutton). Then proceed with the testing.

When you disconnect the horn to button wire the simplest thing is to take that wire and ground it directly (touch it to the crankcase or head or any other bare metal that's well grounded). If the ignition is turned on that should sound the horn if your horn power pack is okay. If it doesn't then check the button.

I have a single wire horn button. I took the horn apart and took some measurement based on a instruction sheet I downloaded. The horn seems to do what it should. I have not run a wire from the battery to see if the horn is working that will be my next step.

Carl

I have a small spare battery I keep charged and a couple of leads with alligator clips I use for testing things like horns, lights, relays, etc. Take the wires off the device connectors and clip the device directly to the battery. That'll tell you if it's any good before you start looking further.