[DanEC]

If I remember correctly, when my VR was not "stimulated" to start "regulating" (maybe it needed Viagara), and I was getting just 12 volts out of my perfectly good alternator, which is not enought to charge the battery other than when it is discharged down to below somewhere around 9 or 10 volts. In other words the VR wasn't telling the alternator that it needed to step up to 14 volts output in order to charge the battery. As I recall the roughly 14 Volts charge is necessary to overcome the roughly 12.7 volts in a battery and actually begin to charge it. With the 4 wire alternator, the circuit to the VR that comes from the red light on the dash, somehow "excites" or stimulates the VR into action. So, if your red light is not glowing but you only have 12 volts out of the alternator when the motor is running - I would be looking at a new VR. If the red light is on while the motor is running then there may not be enough resistance in that circuit to the VR to turn it on. ERA provided me with a resistor to wire in on the red light "charge" circuit to get mine working.

However, if Patrick is out there he can provide a much more comprehensive trouble shooting process.