2002 Yamaha YFM660 Grizzly factory service and repair manual, Page 397Get this manual
2WD4WD SELECTING SYSTEM EB803020
TROUBLESHOOTING IF THE FOUR-WHEEL DRIVE INDICATOR FAILS TO COME ON:
Procedure Check: 1.Fuse (main, four-wheel drive) 2.Battery 3.Main switch 4.Four-wheel drive relay 5.Four-wheel drive relay 6.Four-wheel drive relay 3
7.On-command four-wheel drive switch and differential gear lock switch 8.Gear motor 9.Wiring connections (the entire 2WD4WD selecting system)
NOTE: Remove the following part(s) before troubleshooting: 1)Seat 2)Front carrier 3)Front fender Use the following special tool(s) for troubleshooting