2001 Yamaha YFM660 Raptor Factory Service Manual, Page 304Get this manual
LIGHTING SYSTEM EB805010
TROUBLESHOOTING IF THE HEADLIGHT ANDOR TAILBRAKE LIGHT FAIL TO COME ON:
Procedure Check: 1.Fuse 2.Battery 3.Main switch
4.Lights switch 5.Wiring connections (the entire lighting system)
OTE: Remove the following part(s) before troubleshooting: 1)Seat 2)Front fender Use the following special tool(s) for troubleshooting
Pocket tester: PNYU-03112, 90890-03112