OK, now that our troubleshooting looks to have isolated the problem the situation leads to this....
As I said up up above, the seat switch connector has a built in foolproof system that is not totally foolproof.
I could have presented this in the beginning but I wanted to make sure everything else was eliminated.
Watch these videos and you will understand the big picture.....
https://www.youtube.com/watch?v=qxUc5O7MPkA
https://www.youtube.com/watch?v=PB7E9RErCDg&t=6s