Electrical System Check
Engine Wiring HarnessMulti-plug loose. Broken wire. Corroded pins in multi-plug. Water ingress into plug (+lead/pin will fizz away in short period of time).
AlternatorDefective rectifier (within the unit). Field windings/brushes worn out. Loss of field magnetism. Loose wiring on back of alternator. Loose or broken drive belts.
Starter MotorWater ingress. Failed solenoid. Loose battery cables. Field windings burnt out. Bendix stuck.
Main Earth LeadCorroded terminal. Come loose giving poor connection.
BatteryFlat. Low on distillate. Shorted plates. Reached the end of its life. Corroded or broken terminals.
Battery Isolator SwitchCorroded or loose terminals. Defective switch. Internal contacts burnt or worn out.