You plug headphones in and the sound keeps coming out of the speaker. Or nothing plays at all. Or the phone thinks headphones are connected when nothing is plugged in, so the speaker stays silent permanently. All three are the same family of problem, and most of them are fixable in a few minutes with a toothpick.
The short answer
Lint compacted in the port is the most common cause by a wide margin. Power the phone off and carefully clear the socket with a wooden toothpick. If the phone believes headphones are plugged in when they are not, that is usually debris bridging a contact, or moisture. Restart after cleaning, because the phone caches its idea of what is connected.
The lint problem
A headphone socket is an open hole that spends its life in a pocket. Over a year it fills with compacted fabric fibres, and the plug can no longer seat fully. Because the socket has several contact rings along its length, a plug that sits a millimetre short makes some connections and not others. That produces the classic symptoms: audio in one ear only, no microphone, or the phone not registering the plug at all.
The same applies to USB-C, which is a tighter fit and just as vulnerable. A USB-C port that will not accept a plug fully is nearly always full of lint rather than broken.
Look into the port with a torch
You are looking for a grey felt-like plug of compacted fibre at the bottom. In a USB-C port, look for debris packed around the central tongue. If you can see it, you have found your problem.
Power the phone off before cleaning
This avoids shorting contacts while you work, and it means the phone re-detects what is connected when it starts up again.
Clear the port with a wooden toothpick
Work gently around the edges and scrape toward yourself, pulling material out rather than pushing it deeper. Never use a metal pin, a paperclip or a needle. Take your time: this usually produces a surprising amount of compacted fluff.
Try sticky tack for the last of it
Press a small piece of reusable adhesive putty onto the end of the toothpick, push it lightly into the port and withdraw it. It lifts the fine fibres a toothpick leaves behind. Use it sparingly so none stays in the port.
Restart the phone
The phone caches its belief about what is plugged in. A restart after cleaning clears a stuck headphone state, which is why cleaning sometimes appears not to have worked until you restart.
Test with different headphones
Rule out the headphones themselves, and the cable, before concluding the port is at fault. Borrow a pair you know work.
Check the adapter if you use one
USB-C and Lightning to 3.5 mm adapters fail frequently, and cheap ones fail fastest. If your audio goes through an adapter, that is a likelier suspect than the phone.
Check the audio output setting
Look in the phone’s sound settings or the media output selector for where audio is being routed. A phone still routing to a Bluetooth device that is out of range behaves exactly like a broken headphone jack.
If the phone shows a headphone icon with nothing plugged in, plug headphones in and unplug them a few times firmly. That often clears the mechanical detect switch inside the socket. If it persists, the switch is stuck on debris and the port needs proper cleaning.
USB-C audio specifics
USB-C audio has an extra layer of complexity. Some phones support analogue audio over USB-C, which works with simple passive adapters. Others only support digital audio, which requires an adapter containing a digital to analogue converter. A passive adapter on a digital-only phone produces silence, and nothing about it looks wrong.
If your adapter worked on an old phone and not a new one, or vice versa, this is almost certainly why. The fix is an active adapter with a converter built in.
Never use compressed air directly into a headphone socket or USB-C port. The pressure drives debris deeper and can damage the detect switch. Mechanical removal with a wooden tool is slower and much safer.
When it is the port
Signs that the socket itself has failed: audio cuts in and out when the cable is wiggled, the plug feels loose or does not click home, the port is visibly damaged or has a bent contact, or the problem persists across several sets of headphones after a thorough clean.
Headphone sockets are usually on a small separate board rather than the main logic board, which makes replacement a reasonably economical repair. Ask for a quote before dismissing it, particularly if the phone is otherwise in good condition.
Why does my phone think headphones are plugged in?
Debris bridging the detect switch inside the socket, or moisture. Clean the port carefully and restart. Plugging and unplugging headphones a few times sometimes releases a stuck switch.
Can I clean a headphone jack myself?
Yes, with a wooden toothpick and patience, with the phone powered off. Avoid metal tools and compressed air, both of which cause more harm than the lint did.
Why does my USB-C adapter work on one phone but not another?
Some phones output analogue audio over USB-C and some only digital. A passive adapter needs a phone that supports analogue output. An active adapter with a built-in converter works on both.
Sound comes out of only one earpiece. Is that the port?
It can be, if the plug is not seating fully because of lint. It can equally be the headphone cable. Test the headphones on another device to tell the two apart.
Is a headphone jack repair expensive?
Usually moderate, because on most phones the socket sits on a small secondary board rather than the main one. It is worth getting a quote before writing the phone off.
The bottom line
Shine a torch in the port and clean it out with a wooden toothpick, because lint explains most of these and costs nothing to fix. Restart afterwards, since the phone caches what it thinks is connected. Test different headphones and a different adapter before blaming the socket, and if audio cuts in and out when you wiggle the cable, the port itself needs replacing.
