Modern Vespa

2006 Stella.

Headlight both high and low finally stopped working.

For a number of years it would shutoff when the headset was turned all the way to one side.

Hi-Lo switch appears to be working.
No continuity on main wire from regulator to H-L switch.

1) I'm thinking the wiring harness has to be replaced due to continuity issues. Looking for some alternative. Even if I could remove the headset and I spotted a break in the wire, I won't be able to patch it at that location where the wear is likely occurring? Is that correct?

2) regulator is putting out about 4 volts to the wire that goes to the H-L switch. This seems very low. I am confused by this. (The regulator was recently replaced in an attempt to eliminate that as an issue).

3) Other issues that popped up when investigating the headlight.

A) The turn signal switch to on causes neutral indicator light to blink, while turn signal indicators remain off.

B) Rear turn signals don't work, but front do.

C) Rear running light doesn't work. But, rear brake light does.

Any thoughts appreciated. Thank you

Have you checked the wiring at the back of the switches? LML's are notorious for having wires pulling off from the back of the switches.

What are the electrical connections like? Are they dry and corroded? What are the earth's like?

Start with checking the basic stuff before you go replacing anything.

Start by checking for shorts on the wires that run from the frame up into the headset. I have a 2005 Stella, and I've replaced nearly all of the wiring between the headset and the frame over the years. The original wiring started failing after about five years for me, so you did better than I did if you've made it this long.

The harness is really too short, IMO, so it pulls the wiring on turns and they eventually wear through and cause problems like you describe. Riding when your horn sounds every time you turn left is awesome.

I also had the hi beam wire just break between the switch and the bulb, for no apparent reason. And I've had a variety of other wiring issues on that bike, mostly resulting in me either replacing or splicing the wire in question.