Modern Vespa

I took the headlight cover off to upgrade my bulbs to LED and I am sure I did not disconnect this male plug on the bike side, nor do I see an empty female plug on the cover side for it to go into, in case I've forgotten.

It has a pink and blue/white wire and is on the left side. It is not the turn signal plug.

Anyone know what it is for?

And can you confirm on my bike it is not normally connected?

It's not normally connected - it just a spare turn signal connector. Useful if you want to add a turn signal bleeper as a reminder.

Thanks!

Has anyone done a mod like you describe? Is there an OEM solution on other bikes and that's why Vespa has it there?

I've done it to every bike I've owned!

My preferred way is to use a diode from each turn signal to the +ve connection of a buzzer or beeper, and wire the -ve connection of that beeper to the output of the brake light switch. This does depend on having incandescent brake light bulbs, not LEDs. This way:

The beeper falls silent when the brake lights are on and working.
The beeper stays working if the brake light switch is faulty.
The beeper won't work at all if the brake lights have blown.

So adds safety in several ways!

if I understand correctly, this mod basically warns you if your brake light is not working? Ingenious!

I thought it was something that would beep when you were using the turn signals, similar to how you hear a clicking sound in a car when your signals are on, as a reminder to turn them off.

what is the actual purpose of this plug on other Vespas that DO use it? i'm confused how it relates to the turn signals. There isn't another spare one on the right side IIRC.

The latter is the main purpose, but wired like this you don't get driven insane at traffic lights with the turn signal reminder hammering at you! The safety aspect is just a silver lining. There doesn't need to be - that has both turn signals on it. Possibly for use with an alarm, before they started to add a dedicated alarm connector, or perhaps to add a future 4-way flasher? AFAIK no other Vespa has such wiring.

Wow, that's a brilliant design by you! Why motorcycle manufacturers haven't done something like you have is beyond me.