Modern Vespa

Stella has a fuse under her left cowling, as expected, but I've found a fuse under the horncast that shouldn't be there, according to the wiring diagram I have (from the MV Wiki page). I can trace the wires, but why is it there to begin with?

That fuse is supposed to be there. It protects the "switching module" which, as I understand it, is a safety *feature* that switches the parking light, tail light, and brake light from DC to AC if the battery is dead.

Interesting. Neither the MV "Stella" wiki page color wiring diagram nor the Haynes manual US spec Stella diagram have that extra fuse symbol (unless I'm just not seeing it).

Good info. I'll pencil it in to the diagram. Thanks.

Yeah, I do not think there is any single diagram that gets it completely right for US market Stellas. The one I attached shows the switching module, but not the neutral indicator light switch. The one you attached shows the neutral indicator light switch, but not the switching module. I have never seen a diagram that shows both.

Also, the diagram you attached shows the external pickup CDI system as was used on older Stellas (through MY 2005). Attached is what I call the "rest of world" diagram. It is different from the US market Stellas in many respects, but it does show the internal pickup CDI system as was used on later Stellas, including 2009s.