I own a 1970 Mercury Colony Park station wagon with the dual action "magic" tailgate. Opens as a door AOKAY but will not drop down as a tailgate. I did verify operation of the center latch when window goes down it actuates movement of center mechanism and allows the pull latch to move and begins to pull LH and RH rod assemblies however the RH and LH upper latches will not release. Cannot get a good visual inside the tailgate to fully understand latch operation. The vehicle is complete and appears all original as it is a survivor. I have the factory manuals but they dont get into details of how the individual latches operate internally. Does anyone have experience with these upper tailgate releases?