Chosen Solution
I recently replaced the keyboard on my mac because there was a liquid spillage on my laptop. Because of the spillage, one of my ports stopped working(I didn’t mind at the time because my other USB port was still working, Everything thing seemed fine and I installed an external WiFi USB called Ac 1200 Dual-band USB 3..0 adapter. That night everything was working including my usb wifi external but the next day randomly that port stopped working. I tried restarting the SMC and for like few seconds-1 min the port was working but then suddenly stopped working. What’s interesting is that the port works when i plug in an android charger but doesn’t work with my iPhone charger(unless i reset the SMC which in that case works for 2 seconds) or my USB WiFi card adapter. Also even though the adapter USB stopped working, I can feel heat from it whenever I take it out of the USB port so maybe the port does work but not actually working properly. On the usb device tree I can see the devices plugged in there. I tried updating my software to the latest one but still no luck. Not sure if I should just replace the logic board. Not sure what to do from here because now i don’t have any working USB ports. My Ethernet, charging, and thunderbolt port work fine though.
Usb ports have different lines as they have to deliver power and exchange data. From your description it seems you have some damage along the the power lines, supplying 5v for connecting devices to work..not a big surprise having liquids presumably reached the board. It might be not a terribly difficult repair, but in my opinion at the same time it would be worth an ultrasonic cleaning to prevent other future damages as parts that have been touched by liquids tend to develop oxide with time and eventually fail. An experienced component level technician would be able to take care of the repair..or you can replace your board, but they are very expensive. In the short run you could look for a thunderbolt to usb adapter.
