pos (+)is always pos.and goes thru the small 2 post fuse and into the trailer to the converter.... neg (-) goes to the frame .
Your trailer has a converter (110v to 12v),probably no inverter (12v to 110v).
Make sure the fuses on the converter are all good ,that includes the 2 - 30 a fuses that are hard to see at first. And the circuit breakers are all on.
You may also have a battery dis-connect somewhere.
It was a rainy few days at Algonquin Prov park...tarps kept us dry.
Wayne --Belle River (Windsor), Ontario
2013 Sunset Trail Reserve 25RB..
2015 White Chev Silverado 2500HD 4x4 (6.0 l gasser)
2003 Mountain Star 890SBRX Truck Camper