I have converted my '73 Dart over to a PriusEPAS system, however it seems it's not giving any assist even in Fail-safe mode. MY question is, It's wired like you said, but does the torque sensor plug need to be plugged in or not to work?
Yes it needs to be plugged in. There should be 4 wires, I believe. I have done the swap. Should be + and - to battery. The 12+ accessory wire and the wire from the epas motor to the module.
Now just so you know the box has to sense "torque" for it assist. I first hooked it up on a bench and nothing happened, until I locked the output shaft into a vise and then turned the input.