2006-2009 Honda TRX680 (TRX 680 FA-FGA) Factory Service Manual, Page 514Get this manual
BATIERYCHARGING SYSTEM
REGULATORRECTIFIER
WIRE HARNESS INSPECTION
Remove the two bol ts and regu lat orrectifierDisconnect he reg ulat or rectifier 3P (Gray) and 3P (Black) connectorsCheck the co nnectors for loose conta cts cor rod ed te rmi nalsBATTERY LINE
Measur he vol tage betw een th Red ire te rm inal and round
There should be battery vo ltag at atl timesGROU ND LIN E