Here's what you should do if only one of your AirPods is working

If only one of your AirPods is producing sound, it's probably a charging issue. Begin by cleaning the charging port of the AirPods' case and making sure the case itself is fully charged. Since grime can build up inside the case, clean there too, especially at the bottom where the earbuds make contact to charge.

Then, charge both AirPods for 30 seconds before opening the case near your iPhone, at which point a popup will appear showing the charge status of the case and AirPods. If you need to check this often, you can do so faster by adding a Batteries widget to your iPhone's home screen. Assuming everything is charging correctly, test the malfunctioning AirPod (keeping the functioning one closed in the case). If it's working, charge both AirPods another 30 seconds and test them again.

In case it's still not working, it's time for a reset. This puts your AirPods' settings back to their defaults, but should otherwise be painless. 

If you have the AirPods 3, AirPods Pro 2, or older models of either: put your AirPods in their case with the lid closed, wait 30 seconds, then go to Settings > Bluetooth on your iPhone. Assuming your AirPods appear, tap the i icon next to them and choose Forget This Device. If they don't, open the lid of the case, hold the circular setup button on the back for 15 seconds, then wait for the light on the front of the case to flash amber and white. At that point, follow the instructions on your device's screen.

If you're using either model of the AirPods 5, any AirPods 4, or AirPods Pro 3, the reset process is similar. However, the input on the physical button is different. Instead of holding it, you'll need to double-tap the front of the case while the status light is on, then double-tap again when that light flashes white, and do the same a third time when the light flashes faster. The same amber-to-white pattern should run, then instructions will appear onscreen.