For anybody that has surge brakes on their trailer, you may have a problem. If you have a backup relay on your surge brakes to release them for backing up, the center pin on the 7 pin hookup does not supply the power when you put your vehicle in reverse.
I just got my hitch and wireing harness installed today. I then read your post about the center portion of the plug not being connected to the back up lights. Why do you think honda omitted this. I am now going to have to find a way to get power back there to release the brakes when backing up. Did you come up with any way to get around it?
My uncle had the same problem, he's a big time fisherman too (competitively even). I guess he took the truck back to the dealer and told them to either fix it or give him his money back, so they fixed it. It was apparently a rather major ordeal.
The reading that I've done on the subject (because this whole trailer braking thing is new to me) would lead me to buy a boat trailer with the kind of surge brakes that automatically disengage themselves when the wheels are rolling backwards. Sounds like a no-brainer. I suppose if you're bent on getting disk brakes then you're stuck with the electric tie-in to the reverse lights. While I'm generally predisposed to disk brakes I think that in this case I'd go for the drums with the automatic reverse disengage.
Its obvious that the Ridgeline was designed to tow trailers equipped with electric brakes, thus the pre-wiring for brake controllers. It would also do just fine with the automatic reverse disengage type of surge brakes. They must not have had any fishermen with the other type of surge brakes in any of their focus groups or they probably would have taken that into account during developement.
I mentioned this in another thread and someone else claims they had a different experience. Anyway here goes again: the owners manual says that the backup lights are wired and doesn't mention the battery charge lead at all. I found that the battery charge lead was hot and that the backup lights were not connected when I installed the factory wiring harness (just as you have described).
I did go ahead and wire the backup lights - I ran a lead up to the left side tail light and pulled power from there. The difficult thing is that the Honda trailer plug is not wired internally for the backup light pin. I adapted a female spade connector (the front of the plug can be pulled out and it has male spade connectors that plug into the back part of the plug). In other words it takes some fiddling but is doable.
Back to trailer brakes - living near Puget Sound (read: salt water) and having had boats for a number of years this is a topic near and dear to my heart. First for those unfamiliar with boat trailers - they come with surge (hydraulic) brakes because electric brakes would corrode and die in about 1 use in salt water. Even the hydraulic brakes last only a couple of years. If you have drum brakes they are generally designed to be inherently "self releasing" in reverse. You usually can back against them unless you are going up a steep hill (I used to have a really steep driveway and so I fashioned a metal wedge to keep the hydraulics from activating when I backed in). Disk brakes are becoming more common and as they come in stainless and aluminum they are have a much longer life BUT they work as well in reverse as in forward. They are set up with a release solenoid that is attached to your backup lights which inactivates them in reverse (or you will NOT be able to back the trailer) - this is the situation where you really want that center post to be connected.