In our 2015 Fleet front dinette, I've redone the "grid", I removed the factory 12V outlet and USB port unit placing 12V outlets behind the seats on the kitchen unit (left side) and the cabinet unit (right side), and in the center, below the front window. The wire gauge to the factory 12V is at least 16ga, might be 14g and definitely not 12ga.
But have a look in your rig - remove the four screws on the 12V/USB/120V panel and gently inch it forward until you can see the wire going to the 12V outlet. The risk is for the wire to the 12V outlet to pop it off. If that happens, remove the two left most screws and temporarily replace them with 1/2" longer screws, screwed in partway, on the kitchen unit fascia. Find /build a support that the right front edge of the fascia will rest on. Remove the remaining screws and pull the right side of the fascia out. Now you can get your hands in to reconnect the wire.