Half Screen is Dark on TCL 55us5800 HDTV

At first, I thought it was the LED lights, when the screen is on, it, fades from bright on the left side to extremely dark on the right side, all while still being able to see images, but when I open up the TV and unplug the right ribbon cable on the tcon board, the right side is bright white, while the left side fades dark from the left to the middle of the screen.