Try not to fall out of your chairs laughing at me, but, I figured out why key fob wouldn't work...

When I switched the guts out I missed the little transponder (?) imbedded in the old FOB. Moved it over and it worked perfectly first try! I feel so dumb...

The picture below is not my FOB, just one I found on the internet, but, what I circled in blue is the part I'm referencing.