2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 338Get this manual
LIGHTING SYSTEM LIGHTING SYSTEM CHECK 1.If the headlights fail to come on: 1.Bulb and bulb socket
EB805020
NO CONTINUITY
Check the bulb and bulb socket for continuityCONTINUITY Replace the bulb andor bulb socket
2.Voltage