Modern Vespa

Hello, the fuel gauge in my GTS250 has intermittently begun showing the proper fuel level and then instantly changing to ZERO fuel and illuminating the Low Fuel light.

I am thinking that this issue is related to a wiring problem as the fuel sender would not show the same symptoms if it was getting stuck.

Do any of you know of a good diagnostic process that I can use for troubleshooting the wiring or maybe are aware of this being a known problem with the GTS?

I have added a few photos to demonstrate the problem. The photos were taken at different times, so please ignore the mileage. Both times, the fuel tank was actually full.

Thanks

Although it just might be possible there's a problem with wiring (chafing etc) my bet is that a connector has become a bit corroded and needs re-seating - or that a crimp at a connector is corroded.

I'd start be re-seating the connector in the headset, after examining it carefully. Also while you're there, examine the condition of the whole headset foil wiring - after this many years it may well show signs of fatigue.

The OP doesn't state the year but it is a GTS250 so a number of years with low mileage.
In addition to the headset, check the connector from the sending unit on top of the fuel tank. You probably have to drop the fuel tank partially to access that connector