[VetteVet]

Well If I am reading your post correctly, you are wiring the large post on the alternator to the battery terminal, but you are also wiring the plug-in on the original harness to the large post as well. Then you say that you got rid of the original harness. What did you do with the wires that went to the plug? If you jumped the plug sensor wire to the large post on the alternator then it was not necessary because the alternator is self exciting and the only thing needed is a wire to the positive battery terminal. That's why it's called a one-wire alternator.