For those of you who'd like to turn off the lighted Vizio logo on your TV, here's how to do it. Just open the back of the TV and unplug the connector to the logo light. The instructions here show a Vizio M320NV, but are likely very similar for other Vizio TVs.
1. Lay the TV face down on a soft surface.
2. Unscrew the 12 screws holding the back on, and two more holding the connector panel in place.
3. Pull straight out on the "Jog switch" knob to remove it.
4. Lift off the back cover. It's quite light.
5. The inside of the TV looks like the first image below, where the lighted logo is beneath the bottom center metal support that the stand post screws onto. The connector for the logo light is on the right circuit board.
6. Looking under that metal support, you can see the three wire cable feeding the logo light in the second picture.
7. The third picture's a closeup of the connector with the red/white/yellow cable, as you'll find it attached.
8. Hook fingernails of two opposing fingers in the connector notches, and pull the connector off. It only takes a little force and looks like the fourth picture when it's unplugged.
9. To keep the connector from flopping around, tuck it under the other wires as shown in the fifth picture.
10. Put the back cover on, attaching the Jog switch and replacing the 14 screws.
That's all you need to do. When you turn on your TV the Logo will be unlit!