If you use the DIAG output, only the setup menu will be visible on the TV. So you couldn’t demo a movie.
The 2 pin cheater would work although be careful that the car’s 110volt isn’t "dirty" DC/AC convertor which might cause noise or issues.
The 2 pin cheater would work although be careful that the car’s 110volt isn’t "dirty" DC/AC convertor which might cause noise or issues.