Controller Doesn't Work Properly!

Those two symptoms together are a useful clue: movement without input usually points to a drifting stick, while buttons that fail only at random times usually points to a connection, seating, or button-contact problem. Test them separately instead of treating the whole controller as one fault.

1. Find which controller is at fault. Test each controller on its own, in the same game, and note whether the unwanted movement and the dead buttons always come from the same controller. If only one controller is affected, do not replace or open both.

2. Rest test and deadzone check. Leave the sticks untouched in a menu and watch whether the game moves on its own. Then move each stick slowly through its full range and let go. If movement always drifts in one direction, or the stick does not settle at centre, that is drift, not a game setting.

3. Reseat, clean, and recalibrate. Detach and reattach the controller firmly, clean the rails and contacts carefully, and run the system's controller calibration. Then test again in a second game. If the problem follows the controller to another game, it is in the controller, not that one title.

4. Test every button and stick on a PC if you can connect the controller by USB or Bluetooth, thentest your controller online, and press each button, move both sticks fully, and squeeze both triggers. If a button registers on a PC but not on the Switch, the fault is more likely seating or a Switch-side setting. If the same button fails everywhere, its contact or membrane is the suspect.

5. If drift remains after cleaning and recalibration, or a button fails consistently in every test, the stick or button assembly needs repair or replacement. Do not keep forcing a sticking button, as that can damage the contact further.

Disclosure: I run this free tester.