I know this thread is old. I had the same issue. We were on a car trip using the DVD players and they just stopped working. I knew it must be a fuse but couldn’t locate which in the fuse diagram. I called the dealership that perhaps they could tell me which fuse but they only wanted me to bring it in and pay $150 to figure out the problem. Finally I have located the black box and the fuse for the DVD player to under my steering wheel. The wires and black box were zip tied up in there so I cut those and was able to access it. 5 amp fuse in a wired in fuse holder.
