The Nintendo Switch comes with two Joy-Con controllers. This guide shows how to replace the joystick of the left Joy-Con. The procedure for repairing the right Joy-Con is different, so be sure to follow the correct set of instructions for your controller.
Insert an opening pick into the seam at the bottom edge of the controller (opposite the L and ZL buttons).
Slowly slide the flat edge of your opening pick up the side of the Joy-Con.
Be careful not to slide the opening pick too far inside the Joy-Con. This may damage the inner components. The back panel loosens fairly easily, so not much pressure is needed.
Use a spudger to gently pry the battery connector straight up from its socket on the motherboard. This will keep the Joy-Con from powering on during the repair.
Be very careful as you pry up the connector—if it doesn't come up with the spudger, try gently pulling the cables straight up from the board to disconnect it.
During reassembly, press the connector straight down into its socket on the board to reconnect the battery.
The ZL button cable is locked in place by a small ZIF connector on the motherboard. Use tweezers or a spudger to flip up the ZIF connector lock opposite the cable.
Use tweezers to gently pull the ZL button flex cable out of the ZIF connector socket. The midframe is now disconnected and can be removed.
The ribbon cable connecting the minus button of the Joy-Con to the motherboard runs over the back of the joystick. It is possible to remove the joystick without disconnecting this cable, but it's much easier to do so when it is disconnected and out of the way.
Unlock the minus button’s ZIF connector and disconnect the cable.
There is a thin black gasket around the hole where the joystick pokes through the Joy-Con. Do your best not to disturb this gasket as you remove the joystick!
Once the Joy-Con is fully reassembled, connect it to your Nintendo Switch and calibrate the new joystick. Additionally, you may need to power cycle your Switch by holding down the power button for 10-15 seconds until it turns off, then turning it back on.