Why is there a dark bar in the middle of my Vizio M658-G1 TV screen?

your panel has a failed connection on the tab driver. this is typically not repairable without special tools, however there is a workaround that may extend your use for a bit longer until it fails completely. plenty of youtube videos explaining how to fix. doesnt matter the brand or model.

youll want to take the back cover off the tv and remove the bezel of the screen to expose the film tabs that is attached to the display itself. there are many all around the unit. look for the tab that is nearest the bars on your display.

you can apply pressure to make the connection again to see if the bars disappear. if so, wedge a peice of foam behind it when reassembling to hold the pressure and solve the issue.

if there is no change in the picture when applying any pressure then the chip has already failed and youre looking at a new tv if you want it gone. the screens are uneconomical to change out unless you find an exact model match with a good screen and swap for cheap.

I have a warranty still for the tv after 15 months (Costco extends all TVs to 2 years which is why I only buy from them). So after 15 months of same issue I call Costco, they put a Vizio rep on the phone. They sent me an email to show them photos and video of issue which was easy at that moment although it is intermittent, I use took evidence during a hockey game, perfect back drop, white. Now they’re sending me a 2020 model to replace it. I’ll never buy another Vizio but at least I get a ‘free’ replacement as I should it’s only been 15 months.