Modern Vespa

I added a switch in the kneepad and 12-5v* stepdown (and a fuse) to my fan so I can switch it between normal and manual at around half speed.

Why? Cause I often do prolonged low speed riding after the bike has warmed up. eg couple of hours on highway then turn on to slow rough gravel roads with a low average speed. Also good if stuck in roadworks or heavy traffic. Also going to be useful this coming weekend as I'm riding in a parade at walking pace on a hot day.

How? cut the harness right before the plug to the fan (easiest access, but would have preferred to cut the fan side of the plug instead of the harness), extended these 4 wires to a 3PDT switch. Next took power from the back of usb charge socket (no cut, just two plugs and a Y split in the wire), ran that through a 1amp fuse then into the 12-5v stepdown and then into the switch. all done Still need to add a LED next to the switch.

sorry no pics.

* think I'm going to change to a 7.5v

You should fit a diode in the line back so as no voltage you supply to the fan can leak back to the ecu. diode are directional so make sure its the right was round so voltage can come through it but not back.