Expert: Brad Sears - 10/14/2010

Question
I purchased a 1955 Ford, 6 volt system. In changing the battery I noticed the ground had been switched from positive to negative. I switched the cables back and now have a 6 volt positive ground, except my generator light came on and will not go off. I changed the generator to a 6 volt alternator, positive ground but my generator light still stays on. Can you help me? Thank You.  Ken

Answer
The generator light is operated through the old 6 volt voltage regulator. One side of the gen light is connected to the ignition switch and the other to the G terminal of the regulator. When you turn on the ignition the bulb sees the voltage and the generator because it is not producing acts as a ground and the light lights. When the generators output voltage reaches the same voltage as the ignition, then the light will go off. Now with the alternator you are not using the old 6 volt regulator and if he wiring is still connected it will allow the light to turn on. Contact the maker of the alternator and see what suggestions that they have for controlling the light. As I do not know whose alternator you are using I do not know what wiring configuration they are using.