The schematics for that board would be in the service manual, which you are very unlikely to find. Canon absolutely refuses to provide any information on the repair of their cameras and lenses, so the only manuals you'll find is ones that have been leaked (which usually is only the parts catalog and not the full service manual).
The easiest way to fix this issue will be to just replace the PCB board that the microswitch is on. The microswitch isn't actually on the main PCB board, but rather is attached to the SD card reader board. Since it's not the main PCB board you'll be replacing, you won't need to do any calibrations or anything after replacement of the board.
You can find a replacement SD card reader board for about $32 on eBay. The part number for the board is CG2-4299. Also note that the SD card reader board is identical in the Canon Rebel T5, Canon Rebel T6, and Canon Rebel T7, so a replacement SD card reader board from any of those cameras will work in your Canon Rebel T7. When you receive the replacement board, I recommend double checking the pins inside of the SD card reader as I have received one once that had a bent pin in it before.
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crwdns2934271:0crwdnd2934271:0 Randy Sipkes crwdne2934271:0