If Dirty Harry can't come through, you may try reaching out to Dr. K himself. Apparently he's been retired about 10 years now, but a 2015 post on Hotrodders.com forum (
Dr K's wiring harness diagram needed - Hot Rod Forum : Hotrodders Bulletin Board ) suggested this:
Dr. K in Alabama 205-543-7165
or this:
Try him at 1590 Tabor Cut Off, Gadsden, AL 35904, phone 256-523-3898. Be sure to offer to pay for his services.