1999-2004 Honda TRX400EX FourTrax Service Manual, Page 225Get this manual
BATTERYKHARGING SYSTEM Connect the tachometer NOTE: Read the instructions for tachometer operationRestart the engine, turn the headlight on and shift it to High beamMeasure the voltage on the multitester when the engine runs at 5,000 rpm
STANDARD: Measured battery voltage (page 15-4lc Measured charging voltage45.5 5,000 rpm
REGULATORRECTIFIER
WIRE HARNESS INSPECTION
Disconnect the regulatorlrectifier 6P connectorCheck the connector for loose contact or corroded terminals
BAlTERY LINE
Measure the voltage between the red wire terminal and groundThere should be battery voltage at all times