Pairing Switch controllers with a computer
Hold the small round Sync button (on the rail of a Joy-Con, next to the USB-C port on a Pro Controller) until the player lights sweep, then pair from your computer's Bluetooth settings. Each Joy-Con pairs separately and shows up as its own gamepad with one stick and its half of the buttons. The Pro Controller appears as Pro Controller with the full standard layout. A Pro Controller can also be connected over USB-C, but on Windows it then only reports input while Steam is running, so Bluetooth is simpler for this test.
Checking Joy-Con drift
At rest a Joy-Con stick should read within 0.03 of zero on both axes. Original Joy-Con sticks are the most drift-prone controller sticks on the market, and a value of 0.10 or more at rest is common after a year. Run the drift test to get a percentage. Nintendo offers free Joy-Con repairs in many regions regardless of warranty; the Switch system also has a stick calibration screen under System Settings → Controllers and Sensors → Calibrate Control Sticks that can mask small drift.
Switch 2 Joy-Con 2 and third-party controllers
Joy-Con 2 pair the same way and report the same layout, plus the C button. Third-party Switch pads from 8BitDo, Hori and PowerA generally use Hall effect sticks and show much lower resting values. Some wired third-party pads only work while the Switch mode switch is set to X-input, so flip it if nothing appears.
Frequently asked questions
Only one Joy-Con shows up. Where is the other?
Each Joy-Con is a separate Bluetooth device. Pair the second one too; the tester adds a selector when more than one gamepad is connected.
The Joy-Con stick reads diagonally at rest.
That is typical drift from a worn stick module. Values pointing to a corner mean both axes have shifted. Nintendo's free repair program covers it in most countries.
Does HD rumble work in the test?
No. Switch HD rumble uses a proprietary protocol that browsers do not implement, so the vibration buttons will report no support even on a working controller.