2001 Yamaha YFM660 Raptor Factory Service Manual, Page 306Get this manual
LIGHTING SYSTEM EB805020
CHECKING THE LIGHTING SYSTEM 1.If the headlights fail to come on: 1.Bulb and bulb socket
NO CONTINUITY
Check the bulb and bulb socket for continuityReplace the bulb andor bulb socketCONTINUITY