Thanks for using Just Answer. I will be glad to assist you.
Unfortunately there is no way to "officially" operate the DVD system while the vehicle is in drive. It is illegal to have an entertainment device that can operate in view of the driver. That is why the system must be in park in order to view the DVD.
Some people have developed a system to trick the DVD into believing that the system is in park, even though you are in drive. There have been multiple attempts to reprogram the systems to get around it, but I have not found anyone able to "crack" the system.
These bypass boxes are plug and play, require no wire cutting or splicing, and can be installed in about 20-30 minutes. I have provided a link below to where you can purchase one:
AGAIN, THIS IS NOT AN APPROVED MODIFICATION FOR YOUR VEHICLE. THIS IS ILLEGAL IN MOST STATES, AND YOU WILL GET A TICKET IF A POLICE OFFICER SEES THE DVD PLAYER PLAYING WHILE YOU ARE DRIVING OR STOPPED AT A RED LIGHT.
I WOULD NOT RECOMMEND DOING THIS IN MY PROFESSIONAL OPINION.
But my opinion does not change the fact that this can and is being done!!