If you did your testing right, I know what the issue is.
Just need you to confirm.
I have to get back to work, but if you did what i asked for testing, you have blown the fusible link (pic below). Remove the cover for the positive battery terminal and look in the glass and see if the elements are separated, if so, you have found your issue.
Worth adding that if you blew this fusible link, you would no longer have ignition power, etc. So it sounds like that is probably what happened here.
