2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 351Get this manual
SIGNAL SYSTEM
5.Start switch
C0NTINUITY INCORRECT
Refer to "SWITCH INSPECTION"CORRECT This circuit is not faulty6.If the four-wheel drive indicator light fails to come on: NO CONTINUITY 1.Bulb and bulb socket
Replace the handlebar switch (left)
Check the bulb and bulb socket for continuityCONTINUITY
Replace the bulb andor bulb socket