Originally Posted by txsunrunner
Mine just came on for the first time ever. Battery was drained last night by my own stupidity (headlights on) and a neighbor jumped it this morning. Charged up the whole way on the way to work (reading ~13 by the time I arrived). Did not leave the lights on again (thank god), but now I'm waiting on a friend for a jump yet again... Did I just not charge it up enough? Or did I somehow screw up the alternator? Does the GEN light always mean the alternator's bad, or in this case is it only serving to underscore my stupidity?
The GEN light sits between the alternator and the ignition 'on' circuit. Normally they both have the same voltage so the light stays off. If the alternator stops working, the ignition 'on' side has higher voltage than the alternator side and the light turns on.
Most of the time it's an alternator fault, but can be a wiring problem too.