2002 Yamaha YFM660 Grizzly factory service and repair manual, Page 372Get this manual
LIGHTING SYSTEM EB805010
TROUBLESHOOTING IF THE HEADLIGHT ANDOR TAILLIGHT FAIL TO COME ON:
Procedure Check: 1.Fuse (main, headlight) 2.Battery 3.Main switch
4.Light switch 5.Wiring connections (the entire lighting system)
NOTE: Remove the following part(s) before troubleshooting: 1)Seat 2)Front carrier 3)Front fender panel Use the following special tool(s) for troubleshooting