Replace headlamp bulb and
check other bulbs one by one.
Check if there is power output from power
input wire of light switch by lamp test
Use a piece of wire to short circuit power line and
output line of lighting switch.
Wiring from magneto or ignition
switch to lighting switch is broken
or shorted.
Lamp is lit after short circuit.
Lamp is still not lit after short circuit.
Inner contact of lighting switch
is poorly contacted.
Wiring from lighting switch to lamp
is broken or shorted.
Yes
No
No
Yes