2003 Yamaha YFM400FAR Kodiak Factory Service Manual, Page 345Get this manual
SIGNAL SYSTEM 3.If the reverse indicator light fails to come on: 1.Bulb and bulb socket
Check the bulb and bulb socket for continuityCONTINUITY
NO CONTINUITY
Replace the bulb andor bulb socketNO CONTINUITY
2.Reverse switch Refer to "CHECKING THE SWITCHES"CONTINUITY