My TV is super dim you can barely see it I did the factory reset and still nothing it's 70 inch element bought about a year ago it's started yesterday then after unplugging the times it worked now today same thing
That sounds like the backlight has failed. If the brightness and contrast controls do nothing, then that's likely the case.
All LCD based displays (so other than CRT, plasma or OLED) require some sort of backlighting. Earlier displays used a florescent light behind the LCD panel (and some laptops still do) while most newer TVs use LEDs. With a complete failure like this, either the florescent light failed or the LED controller failed. I don't know what the warranty is on your TV, but if it's beyond 12 months you may be out of luck for warranty repair.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.