2004-2005 660 Yamaha Rhino Factory Service Manual, Page 390Get this manual
SIGNALING SYSTEM 4If the reverse indicator light fails to come on: 1Bulb and bulb socket Check the bulb and bulb socket for continuityCONTINUITY 2Reverse switch Refer to "CHECKING THE SWITCH"CONTINUITY NO CONTINUITY
Replace the bulb andor bulb socketNO CONTINUITY