There are two connectors for the screen, one is for the digitizer and the other is for the LCD. It sounds like you got the digitizer plugged back in correctly, but I'm guessing the LCD flex cable isn't seated quite right. Here's the cable you should be checking.
You'll need to open the Switch back up and check that connector. There are two little tabs on either side that should both be butted up against the connector itself; if they're uneven or not inserted all the way you could well have video image problems.
Take a look at that and let us know what you find.
There is a second LCD connector that could conceivably be causing problems if it isn't in all the way.
If you hold a flashlight up to the screen, can you see any image? If so, that would indicate that the backlight is out for some reason. On smartphones it wasn't unusual to blow the backlight circuit either on the LCD or on the logic board if you plugged and unplugged it with the battery connected, but as far as I know that hasn't been a big issue with the Switch so far.
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My switch is on but the screen is just black and no light is coming from it can you help
crwdns2934271:0crwdnd2934271:0 Jacob Munguia crwdne2934271:0
@jacobmunguia has any repairs been done to it or has it been opened
crwdns2934271:0crwdnd2934271:0 daniel crwdne2934271:0