I bought a 2012 EX-L with 4WD assuming that the "tow ready 4WD" meant that you plugged in a 7 blade connector in the back and wired a brake controller up front and you were done. I found that Honda has a 34 step process to install the wiring harness and its a huge endeavor.
however from this link:
http://www.piloteers.org/forums/82-2012-pilot/30682-trailer-wiring-harness.html
wahlct Figured out a better way to get it installed without ripping out the back seat

its about a 2 beer job.
the back view of the cargo area with the two cubby holes where a majority of the work is done:
inside the aft cubby hole is another cubby hole
inside of there:
closeup:
The holes on the left side of the insulation is where the control module bolts to. the bolts are 10mm socket, I had a little trouble with a 3/8 drive socket on the top bolt, but a 1/4" socket drive worked perfect. the rectangle on the right is where the wire clip snaps into the frame.
installed: (refer back to this picture later, because the cable at the bottom comes off the relay box)
the kit has one part called the control unit harness. look in the relay box, install the two relays, snap the cover on, and then move to the little cubby hole forward of the one you have been working with. Basically there is nothing in there except a dead ended plug and a seat belt looking tab.
The control unit harness provided in the kit has two connectors on the harness. connect the plug with the one that matches the socket in this hole, and thread the smaller cable behind the plastic column between the cubby holes then slide the relay box over the tab, and it snaps into place:
you already bolted the module to the frame, so just plug in the loose end of the new cable you threaded through between the cubbies to the module you installed earlier, press the wire clip into the hole in the body and add a zip tie to bundle it all together with the yellow wires to look like picture #5 above
next you have to take a razor or whatever tool you want to knock out the piece of plastic in the bumper (by far the longest most tedious part of the entire install), and then mount the 7 blade connector to the bumper with the provided socket bracket:
from the front of the bumper:
unclip the dummy plug from the factory harness, plug in the wire from the trailer socket harness:
the picture above is the dummy plug from the factory. it has to come off to install the socket harness. its a bit of a PITA because the release for the dummy plug is on the aft end of the vehicle and you cant see the little clip to try and manipulate it. I took the whole theing down from the frame and got the dummy plug off the harness, and clipped it all back into place. I got lucky the clip didn't break.
pop the hood, install the 30 amp fuse and you are done.
it does help to have the pdf file to assist with identifying the parts and understanding what goes where, but skip all the BS about ripping the seatbelts and side panels out of the vehicle.
http://www.collegehillshonda.com/instructions/pilot/2012/08l91.pdf
ok maybe it was a 3.5 beer job because the dummy plug got me pretty frustrated.
also, the kit has the adapter for the dashboard plug to install the electric brake controller. I threw it in the glovebox for next weeks entertainment.