Are you talking about on page 9-20 of the owner's manual? If so,
this is it. Older Pathfinders needed a
logic box, but apparently they are now factory installed.
Sorry no one specifically recommended looking at the fuses. But after verifying the trailer is wired correctly, when one discovers you are not getting signal from the vehicle plug, fuses would be the very next thing to check.
Glad you got it fixed.