Chosen Solution
I have a 3DS XL and there are a few buttons that require extra pressure or don’t work at all but I can hear them clicking so I know they are not stuck, left on the dead requires extra pressure, down on the dpad doesn’t work at all, unsure if the x button works though, I have cleaned the pads to eliminate dirt but I fear it may be the buttons on the board itself
Clean the Circuit Board and the Rubber Buttons The best way to clean circuit board and the rubber buttons is cotton + alcohol. Never use water. After cleaning both the circuit board and rubber buttons you should check if the buttons are working before proceeding. The reason is; cleaning the circuit board and rubber buttons most of the time solve the issue. If it’s working. Welldone! Regards, Will