Here is a small picture explaining the problem. When plugging a charger.
Left is port #3, right is port #4.
When plugged in port#4 it is the expected behaviour, leds are on, and laptop is charging. In port #3 even the charger led is off (I don’t know what it means, it doesnt feel right, this is a Dell XPS charger)
Jonathan is correct either there is hardware damage to the port and it is inoperable or the EC recognized something was wrong with the port and disabled it so it did not cause further damage to the rest of the components.
Talk with support. They are the best resources when it comes to diagnosing what is wrong.
It is possible that the port has been disabled by the EC and resetting the mainboard and disconnecting/reconnecting the battery may reinitialize the EC to test all the ports for functionality.
Thankfully there are three other ports that presumably are still working as intended. Shorts and malfunctions happen all the time. More so in the wintertime with static shocks not playing nice with electronics.
I believe USB power supplies (PD or not) usually output 5V by default regardless of if they’re connected to anything. In any case, my dell charger definitely lights up if not connected to anything.
I guess my knowledge is a bit outdated. So in this case, the Dell charger originally has 5V output, when plugged to the good port it then negotiated 20V, while on the bad port it shut itself down. Short circuit is a possible cause
