i have found 2 types of 7-pin connectors
one has flat blades and the other has round pins
the flat blade style is most commonly used on vehicles w/ factory towing packages specifically on Jeeps & pick ups
i have SEVERAL trailers that came from the factories w/ 7-pin plugs that utilize the flat blades and they all fit & functioned properly
SO there must be a kind of camaraderie amongst trailer manyfacturers that is manifested in their wiring procedures
whether they build utility trailers, farm trailers, boat trailers or travel trailers ALL SAME...
when i goto TSC and buy the plugs/parts needed to repair my trailers i find that each package has a wiring diagram in it showing the purpose of each of the terminals and in most(not all) cases the terminals are marked in some logical manner
that being said, my Jeep Cherokee & my F-350 came with factory towing packages and the terminals in the 7-pin flat blade plugs work the same with all my trailers
i can even do my annual light check on the family 5th wheel travel trailer using the Jeep as the source of electrons
using the 7-pin connector and having the ability to charge the trailer coach battery while running down the road makes good sense
while you're at it consider using weatherproof solderless connectors everywhere they could be exposed
they are a bit more expensive and involve one more step(heating them) going in butt IMHO will save you over the long haul
i know they work since my big boat trailer was wired with them(6 years ago) and it gets a regular dunking(completely submerged) in salt water w/o unplugging from the TV
what i have shared is from personal experience not something i have heard, what "they say" or something i have seen in an internet catalogue
just my 2¢ worth this morning
sw