Reconnect keyboard to mainboard
I followed your tear down instructions, but I cannot figure out how to reconnect the keyboard ribbon to the mainboard. Is there a way to see an exact picture how it is supposed to be? or maybe a video?
I believe that this is what you're looking for .
iFixit says: "The MacBook Pro 15" Retina Display Early 2013 packs the battery, keyboard, trackpad, and upper case into one assembly. If any of these components fail, the entire assembly must be replaced. Use this guide to replace your upper case assembly."
That's why I consider keyboard only replacement on these, and other machines, masochistic (and describe it as such to those who ask about "keyboard only" replacement).
If this answer is acceptable please remember to return and mark it.