I have been having an issue with the 90a alternators I have charging.. I have the alternator going straight to the battery with no tie in to the oe wiring bundle. I have one alternator that works fine this way but my other ones won't kick on and charge. Someone mentioned that the alternators won't charge without the, grounding I guess, from the alternator light. Electrical stuff is not my forte - any suggestions on how to address this? thanks