You might also want to look under the tray on top of the center console. I found an extra set of wires with spade connectors on them that was wired up to the cigarette lighter circuit on the Ford chassis side.
They were hooked up to the 30 amp circuit on the Ford fuse box (in either slot 70 or 72) and was thick gauge wire (I think either 10 or 12 gauge).
I extended it over to the left of the driver’s side and added a USB port with a voltmeter.
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