2013 Supra Sunsport 22v - I've been trying to plug a usb adapter into the DC sockets throughout the boat. First one I plugged in a was a cheap nothing adapter you can get at any convenience store or WalMart and it instantly stopped working. Thought it was kind of weird, but being cheap decided I'd try another one in a different socket, same result. I reset the breakers under the driver side and checked the grounding wires thinking it might be a grounding issue. Even used a voltmeter on each socket and was each one was reading exactly 12V, so I figured it was safe to try a nicer newer adapter and it fried it too. The adapters only pull 1.5amps each. Lastly, I tried an old iTrip I had and same result, it won't turn on, and if I plug it in a truck it won't come on now. I checked my trucks setup and it seems to be the same, 12V at the socket with a 15amp fuse.

I'm at a loss here. Everything I can think of seems to be working as it should be. I know the breakers are 15 amp, but I wouldn't think that means each one of these sockets are constantly pumping out 15 amps. Anyone seen or heard anything like this before? I would really love the help.