problem with electrical system

I just changed the plugin to another exterior outlet. these are standard electrical outlets. The outlets work in the rv as well as the microwave. But the fridge won't work neither will the interior lights until I turn the disconnect to the on position. But when I do the 2 30 amp fuses bloe on the converter. I have two black wires run to the positive terminal to the battery as well as a yellow wire run to the negative. the yellow wire is also ground to the frame. Also at least 1 of the black wires goes to the disconnect.