Just to add to the previous post. If you are in Australia like me then there are caveats to how those jacks work. The earth is not passed back to the video module so plugging video into the socket won't work unless you connect the video ground from your source to the vehicle chassis or you modify the socket PCB to pass the earth through. For some reason its setup to pass th earth only through to the video out socket !!!

You can use them for mono audio in and out as well as video but not stereo sound.

Seedar.