Check the operating conditions
Some vehicle sockets work only in a particular ignition mode; others remain powered for a period after shutdown. The same car may treat its front and luggage-area outlets differently. Check the handbook before deciding that a socket has failed. A supply that turns off as designed is not a reason to dismantle the trim.
The phone is only the final item in a small chain. An adapter indicator may light even when its USB output or cable is not working properly. If everything is undamaged and cool, try a known-good compatible cable or approved low-power adapter as appropriate. Do not keep using a plug that is loose, scorched, cracked or noticeably hot.
Keep the socket clear
Look into an unused socket from a safe position with the vehicle switched off as the handbook directs. If something has fallen inside, do not fish it out with a metal key or screwdriver. An apparently inactive outlet may still be supplied, and a tool can bridge its contacts. Have foreign objects or damaged contacts dealt with safely.
Avoid forcing a plug that does not fit correctly. Check the outlet's permitted load in the handbook and the accessory's requirements, including the total load if a splitter is involved. Do not assume that every socket can run the same appliance. This is especially relevant when a phone charger has been replaced with an inflator or another higher-demand device.
A narrow fault deserves a narrow description
If one outlet fails while the rest of the car starts and operates normally, report that specific pattern. Note which outlet, which accessory and whether the failure happened during use. The circuit may have a protective fuse, but its location and rating must come from the exact handbook. A replacement that fails again needs investigation, not a stronger fuse.
A USB port can also have a different job from a neighbouring power socket: some support particular data functions or charging behaviour. Check the correct section of the handbook before comparing them. If a compatible known-good accessory still does not work under the required conditions, arrange a circuit check. There is little value in condemning the vehicle battery solely because one charger stays dark, especially when the rest of the evidence points to a much smaller area.
