Doug,
If the light is on and the alt is charging properly, then you probably have a one wire alt with an internal regulator that does not have a provision for a warning light. If that is the case, the wire from the light is probably grounding in the engine bay. The wire should be blue with a black stripe.
If you still have the external regulator, then the light wire must be grounding somewhere, and the alt wouldn't be charging properly.
Did this start about the time that you installed the new ignition system?
PM sent.
John