Ford uses the can-bus system so that the factory radio and DVD player can "talk" to each other.
I had a similar situation with my 2007 Ford Freestyle. My dealer/installer of the Z1 was confident that he had a product that would emulate the can-bus, allowing the DVD player to operate on its own. No go. We ended up taking the factory stereo apart, keeping only the main board (with the wiring harness plugs) and the heatsink, modding up the existing case to make it smaller (like a module for the Z1 accessories), wiring up the power and the can-bus. It works like a champ now.
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