1999-2002 TRX400EX Fourtrax Service Manual, Page 225Get this manual
BATTERYICHARGING SYSTEM Connect the tachometer NOlE: 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 rpmSTANDARD: Measured battery voltage (page15-4} Measuredchargingvoltage15.5 Vat 5,000 rpm
REGULATORRECTIFIER
WIRE HARNESS INSPECTION
Disconnectthe regulatorrectifier 6P connectorCheck the connector for loose contact or corroded terminalsBATTERY LINE