So here is the issue. With the alternator wiring pigtail from the alternator there is a 4-pin connector. Only 3-pins are used, two of which got to the ECM. The third originally went to the C100 under hood connector and is labeled a pin "J" Engine on Signal (w/SBA). My question is what is this wire and does it play a part in my application of the 6.0l swap in my '87? Any info even if it is just a pin out for the alternator would be helpful. The only difference from the reference that I am using for the Pinout of this wire(LT1Swap.com) is the actual wire color but location is the same. I'm sure its likely just do to the year that the color changed. Thanks for any help.