Pls have a look at that.....
https://www.kymcoforum.com/index.php?topic=31637.0Needs not to be exactely that cable but shows how our scoots depend on .
First step: put a jump cable from battery minus to motor block (this crocodile ones).
Second: jump cables from a known good or car battery to your scoot battery
Do NOT rely on batteries good outer shape or think when new its good!
Fuses: all out and pulling hard on connecting cables underneath, sometimes rotten.
Lights going dim means usually bad battery or bad ground.
ALL light issues depend on a functional RH light switch (close to throttle) then via harness to LH switch and further to indicators and main, etc.
Go stepwise from battery to connectors RH underseat frame, then to switches on your handlebar.
Somewhere voltage must dissapear.
Ignition switch is not very likely the culprit.