Use this troubleshooting tree when a gamepad tester misbehaves. Work top down: detection first, then buttons, then sticks, then rumble and mapping. Skipping ahead wastes time because stick drift and deadzone pages cannot help if the browser never lists the pad. Keep the Controller Tester and Controller Detection tabs handy while you isolate the fault.
Nothing detected
Follow Controller Not Detected. Press a button after connecting, prefer USB, close exclusive apps, and retry a current desktop browser. Confirm the OS sees the device before you blame the site. Mobile browsers often lack solid Gamepad API support. After the pad appears, retest on the main controller tester so you know the snapshot is live.
Buttons work, sticks drift
Open the Stick Drift Test with thumbs off the sticks. Persistent idle magnitude points to hardware wear. Clean carefully, compare cables, and avoid treating a large deadzone as a permanent fix. Read How to Fix Stick Drift and visualize gates on Deadzone. The companion article Deadzone Explained clarifies why masking drift hurts aim quality.
Rumble missing
Try Vibration over USB in Chromium. Bluetooth paths and Firefox builds vary. Missing browser rumble does not always mean broken motors, because the Gamepad API vibration actuator is optional and inconsistently implemented. If motors work in a native game but not in the browser, treat it as an API or browser limit, not instant hardware failure. Background on those limits is in Gamepad API Explained.
Weird labels or indexes
Unknown mapping means you should trust indexes over Xbox or PlayStation names. Press each control once and write down the index that lights up. Generic DirectInput pads and some Bluetooth modes show this often. Remap inside the game after you confirm every physical control still reports a value on the tester.
PC-specific quirks
On Windows, finish Bluetooth pairing, avoid Game Bar conflicts, and compare wired versus wireless on the PC Controller Tester. More PC context is in Controller on PC. Still stuck after OS visibility is confirmed? Switch browsers, reconnect wired, and verify Device Manager or the system Bluetooth panel first. Extra case notes appear on the blog.
Good troubleshooting is boring on purpose: prove detection, prove each input family, then decide whether the fix is software settings or hardware repair. A calm pass through this tree turns confusing gamepad tester symptoms into a short list of actions you can finish in one sitting.