Duane,
It sounds like you need an original camera flex cable to fix issue. I say that because your issue seems to be related to my question on testing 7/7+ screens BEFORE installing them. I usually just connect the Dig & LCD cables to test screen. However, on my 1st 7+ screen change I noticed right away that the phone was stuck on the Apple logo when trying to test it. I went ahead and finished the screen replacement & connected all the cables, including the camera flex...and it worked fine. So it appears that the camera flex has to be connected to even test the screen before replacement.