Check and clean all the wiring connections associated with the alt. and battery. Check to ensure the alt. casing is directly grounded to the engine block properly. Failing that, you could possibly have a break in the wiring somewhere. Are you sure your battery is ok? To check if your alt. is charging at all, blip your throttle from idle and see if the headlights brighten up a little. If they do, that could point to a dead battery. Checked the electrolyte level at all? Try that and report back if still having problems!