Under the hood, near the driver side headlamp there is an old school electrical conduit(i forgot what it was called) but anyway, if the circuits on that board are bad, you will not charge, and a diognostic will say bad alternator, and you will have no power...lights will be dim.
Buy a replacement at AutoZone for 12-13 bucks! Found this out last night after hours of (what the hell!!??)