Factory DVD System 2004 Yukon

I have a factory issue roof mounted Panasonic DVD that was pulled out of a 2004 Denali. I have one major problem, there is no wiring harness with the unit. GM says get it from Panasonic, they say get it from GM.
Is there anywhere to find a replacement wiring harness for this unit?
Any help will be appreciated greatly. Local audio stores have not been able to help.