2005-2006 Honda ATV TRX500FE/FM/TM FourTrax Foreman Factory Service Manual, Page 381Get this manual
ELECTRIC STARTER
INSPECTION
Remove the seat (page 3-4)Remove fuse box cover and the diode
Check for continuity between the diode terminalsWhen there is continuity, small resistance value will registerIf there is continuity in one direction, the diode is normal