[cmspaz]

As I said earlier, first thing to look at is the fusible link, if that's good, check the connections on either side where the wires from the alt and battery hit the fuse box, might be corrosion there causing it.

If that all looks good run a jumper wire from the hot connection on the alt directly to the battery and see if it works then, if so you've got a break in one of the aforementioned wires.

If neither of those prove to be the culprit, that means the voltage regulator isn't coming on. Since you know it works via test bench, the only possible cause would be a lack of signal from the ECU, be it caused by a wiring break or faulty ECU.