Please read the red text. Then read the yellow text. If you don't have a FLEX or MKT vehicle, then playing a dvd in the control head will not play on headrest monitors. You CAN play a dvd in Headrest A and using the Sound Select, it will play through the vehicle's speakers. I have verified that this works in mine. Flex and MKT were equipped with My Ford Touch or My Lincoln Touch screens, not the type of units in the 3rd gen Expeditions. Hate so say it but it's not Ford's fault, it's misreading the text I have quoted below (again)
REAR DVD SYSTEM (IF EQUIPPED)
Note: The images seen in this section, and the functions they represent,
are only available with the headrest DVD system and are only available
on Flex and MKT vehicles if the headrest DVD option is ordered
from the factory when ordering the vehicle. For all other headrest
DVD systems installed on vehicles other than the Flex and MKT, or for
headrest DVD systems installed on vehicles already available in a dealer
inventory, these functions are NOT available. Your navigation system allows you to access the dual DVD headrest
system (if equipped). To access:
1. Press the MEDIA hard button on the navigation system.