ALTERNATOR12-8 TNV DI Service ManualAlternator TroubleshootingALTERNATOR TROUBLESHOOTINGTurn key switch ON.Does battery indicatorturn ON?At idle, does batteryindicator turn OFF?Does battery indicatorcome ON?Ground drive machine sideL terminal. Does batteryindicator turn on?Does battery indicatorcome ON?Start Engine.ONOFFOFF OFFOFFONONOFFBattery indicator ON.Disconnect harness L terminaland IG terminal at alternatorIncrease engine speed to1500 rpm. Turn light switch ON.With engine running at 1500rpm, measure voltage atbattery.Notes:1) Use a fully charged battery2) DC voltmeter: 0 to 30 V, 0.5 class3) The check method is also applicable to the bench testWith engine idling,measure voltage at Lterminal and at battery.With engine idling,turn light switch ON.Replace the battery indicator.Battery indicator is available fromdriven machine manufacturer.Battery indicator flashes.Battery voltageis between 13and 15 volts.Battery voltage greaterthan 15.5 volts.Battery voltage minusL terminal voltage isgreater than 0.5 volt.Battery voltage minusL terminal voltage isless than 0.5 volt.Battery indicatoris dim.Battery indicatoris dim.Inspect rotor assembly andbrushes.Excessive voltage drop betweenBAT and batt ( + side) terminal.Check condition of L terminal.Inspect diode negative (-) side.Replace regulator.Inspect auxiliary diode.Not abnormal.Inspect or replace V-belt.Inspect alternator.Inspect diode positive (+) side.
