Trailer Wiring Install Question

[kg5ie]

Installing Professional Wiring Products trailer harness on 2008 Rogue. Instructions say to gain power to the trailer isolation box by using the plug taped to the harness running along the driver side. Found harness and plug mates to connector supplied. However, that plug is dead. No power to it even with engine running, lights on, etc.

Alternative instructions say to run a wire to the battery. I have the plug described and should not have to do that. Is there a fuse thta has to be added to make the plug live?

[vpnavy]

Check all your fuses (especially the box under the hood).

[deeznuts]

See if your missing a "trailer" relay or two

[15pointsroad]

Where are the fuses for trailer lights???