Modern Vespa

I was in the house today,,,and I heard a crazy loud noise coming from the garage. It was my unaccompanied Vespa GTV300.
I tried pushing on the horn a couple times, and it would not shut off.
I placed keys in the ignition and started the engine, and pushed the horn button. It shut off…then came on again. After a few more times, it finally shut off.
I installed an aftermarket horn 6 years ago (it is LOUD), and have NEVER had this happen.
Anyone have this happen to them before?

I would immediately suspect the wiring to the new horn. I assume it has it's own relay. Is this fed direct from the battery, with control from the horn switch?

Yes… it was a plug and play.
Disconnect old horn,,,plug in new.

I have had it for six years…this is the very first time this has happened.
AJ

Er - I think you mean 'No... it was a plug and play'. 'Yes' would have meant you added a relay, which if it was plug and play you did not.

In which case you must have the very rare circumstance of both the horn switch going short and the ignition switch going short, OR somehow a 12V feed direct from the battery (these are rare) has shorted to the horn wire from the horn switch.

Time to get that meter out...

Thanks Jim,
I am going to check things under the knee pad cover tomorrow.
I "DID" give my scoot a good washing this morning, perhaps some moisture got into something.
Took it out for a short ride this evening…as the cool air was calling, and the horn did not work. Blew a fuse maybe? I am trying to recall if it had an inline fuse.

There'd only be an extra inline fuse if you'd added a relay. If it was just swapping the horn units (plug'n'play) there's no extra wiring.

Hopefully this is somewhat related. A month or so ago my wife woke me up telling me"your truck's horn is blowing."

In the end it was a failed relay. I'm told this is somewhat common with horns and relays. I have no idea why it occurred.

The good news is the relay was cheap!