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.

[nortonfb]

Check the horn fuse under the hood, that will throw the battery symbol.

[CTScott]

Originally Posted by nortonfb

Check the horn fuse under the hood, that will throw the battery symbol.

What you talkin bout Willis?

On the 4 pin alternator connector:

White: Feedback via the ALT-S fuse (check that fuse)
Green: Ignition switched power (via the 10A Gauge fuse - check that too)
Blue: Charging indicator output (should be +12 volts with alt running)
Pink: Output to AC and ECM to let them know alt is working

Also, check the two large fusible links built into the positive battery terminal. It is easy to short the wire from the battery to the alternator when changing the alternator and doing so will pop one of these.

[Tylervanpool]

I checked the fuses and they look good. The wiring harness itself looks bad from the car. Looking somewhere to buy a replacement