The above is wiring circuit for alternator. If you turn on headlites with engine off, that is battery voltage. Use a digital multimeter across battery posts, everything turned off. 12.6 volts is considered a full charge. Start the vehicle, take second reading across battery posts, the second reading should be higher than the first, if it isn't, the alternator isn't charging for some reason. you can also take a reading at alternator bat terminal, same deal.
Wednesday, November 11th, 2009 AT 2:34 PM