LCD “grounds” and ceases to work ONLY when assembled!?!

Replaced LCD on iPhone 6SPlus. Final test before joining and reassembling to reinsert iPhone “panty-lock” screws adjacent to lighting port. All checks out great; digitizer reading on all points, volume up, volume down, Home button check and it works*. All cameras are a green light, speaker, loudspeaker, microphone, and a partridge in a pear tree. All is good, Operation was a success, and once again I declare myself “The Most Brilliant Man Alive!” and I casually close the phone up, screwe it shut and press home……

…..crickets. Screen BACKLIGHT was working, audio was on, etc. The screen’s information was not being displayed at all. No signal. Power? Yes. Signal, No. (just to be clear, by “signal”, I mean “I can’t see a thing on the screen except dark backlight glow”)

I reopened it. I decided to check once more before disconnecting battery and Digi assembly…… A bright and brilliant HIGH Def screen greeted me with a smile and a twinkle that was specifically preprogrammed for me by apple technicians. (It helps me cope with many complexes. Don’t judge me). I found no discrepancies, and I was unable to manually trigger a signal cutoff anywhere by probing with a nylon probe. Upon assembly, my hopes and dreams for any justice in this cruel cruel world ended when I couldn’t get that demon-possessed lcd to come on until I separated the print panel again. Well, to make a long story a few lines longer; The point of contact that I have narrowed it down to is top left corner. Whether the rest of the phone is seated or not, when I seat the top right corner, the signal of info stops. The lcd IS POWERED (I see the glow in low light). But nothing else can be seen. I can’t find the short. Anyone have a favor they can use to figure this one out? Maybe you have a cousin who knows someone that roots through the garbage of someone who cuts the hair of a genie (yeah, you know; GENIE. 3 wishes, etc.), and wants to loan me a wish towards figuring out this phone? Much obliged….