2004-2005 660 Yamaha Rhino Factory Service Manual, Page 409Get this manual
CARBURETOR HEATING SYSTEM
4Thermo switch Remove the thermo switch from the wire harness Connect the pocket tester1) to the thermo switch Immerse the thermo switch in container filled with water Place thermometer in the water Slowly heat the water, than let it cool to the specified temperature as indicated in the table Check the thermo switch for continuity at the temperatures indicated in the table The thermo switch circuit is closed The thermo switch circuit is open