Why is my switch powering off?

Hi Max853,

Personally I'd be very suspicious of the SD card reader itself. From my experience doing a midframe replacement on my granddaughter's Switch, I found that getting that darn thing plugged back in correctly was harder than it looked. Took me a couple of tries and I did end up taking off the foam pad so I could tell when the connector clicked in place.

I'd suggest playing with that; you might as well take a magnifying glass and check the pins on both sides while you're at it. If you find any bent ones they can sometimes be straightened with some fine tip tweezers. Clean them with 90% or higher concentration of isopropyl (rubbing) alcohol and try plugging it in again. If you don't get it the first time, try, try again; it took me multiple attempts to get it in right.

If it refuses to work correctly even after all the fussing you can do with it, my next idea would be to go ahead and replace it and see if that fixes the problem. Here's the iFixit guide for doing that job.

Nintendo Switch Micro SD Card Reader Replacement - iFixit Repair Guide