Alternator Wiring Harness

[Tylervanpool]

Hello,
My battery light is showing on my dash indicator and the Toyota dealership is saying that their test came back showing that I have no charging amperage coming from my alternator to my battery. My alternator is stock but brand new. I personally think there is a problem with voltage going to the alternator through the alternator harness and not telling the alternator to turn on or to charge the battery. Could someone please tell me what each of the 4 wires does that are leading into the harness? I want to test each one with a micrometer but don't want to go probing around on wires I don't need to mess with. I think there is a Yellow/black stripe, black, green, and a blue.