GM accomplishes this by wiring the No. 2 (field) wire into either an indicator ... diode should face toward the No. 1 terminal. If that'sstilltoo complex, get the regulator from a 27-SI-series ...

Q: I have an older model Toyota Corolla and I have a question about the Low Fuel Indicator ... Do I need to pull the alternator and have it checked? A: Sounds like a bad diode.