Alternator issue

[Uniquestrain]

Does anyone know why my alternator isnt switching on to charge my battery? Everything is plugged in right
New alternator too
Im suspecting a bad ecu or wiring

[DesktopDave]

I'll have to look up the wiring diagrams, but IIRC that's a pretty simple system.  Check the grounds, wires and have the battery load tested.  Then check the regulator.  Most auto shops will run a free test of both the battery and alternator.