The charge light on a smart charge system like a transit connect doesn't come directly from alternator, it feed comes from pcm (
engine ecu) , it doesn't excite like conventional systems, pcm control the amount of charge , via blue grey wires red wire is 10amp fuse link given battery voltage reference. If you unplugged three wires alternator will charge it's nuts off when revs applied , fault usually with short wiring from alternator to radiator or under battery tray to fuse box. If you can find broke wires ect you need someone with a scope to test further.
Busted knuckles, January 2017