I would like to know the answer to this as well! I just replaced mine yesterday with (sorry to say) an O'Reilly remanufactured one, still had battery light so took it back, tested and said voltage regulator was bad, replaced making them test new one before I left, said was good, install, and still light on. Drove to Advance and tested said everything was great. Load output was 13.5 volts. Battery is charging and holding good too. Losing my mind!
If I need to get a Motorcraft 200 I will, but would love to hear what others have done and if you figured yours out.