I'm sure your research found it's a LED backlight so dive in and tear it down so you can test each LED.
I am a retired electronics tech and was given a Vizio M601d-A3R TV for repair. The right side of the screen has a shadow on it. Appears to be the only problem. Do not have a remote at this time. Can this be the LED Backlight failure and how can I fix it? Is it worth it?