Alternator Indicator

If lamp remains on when ignition is off, check for shorted alternator positive diode. If lamp remains off when ignition is on, but the engine is not running, check for burned out indicator bulb, an open lamp circuit, or an open in alternator field. If lamp comes on with engine running above idle RPM, check alternator output, check for shorted alternator negative diode. Check for loose or broken alternator belt.