I had basically the same trailer but an 05 1057. This sounds like your Ground Fault, like a previous poster stated. The converter system is quite seemless, and if you blow the ground fault, you wont even notice anything has happened, as your lights wont flicker, or anything. We had to actually install a nightlight and leave it on to ensure 120 was running, or else we would loose stuff in the fridge.
So check your GFI .. should be under the dinnet .. opposite where you stow your stove.