Chosen Solution
Bought a used Xbox One S wireless controller With fresh batteries the power button lights up for half a second and turns off. Successfully connected the controller to PC via USB cable, used Xbox accessories app in Windows 10 to troubleshoot it and found out that the Y and a few others are permanently pressed down. I figure opening up and cleaning some of the button connections could solve the stuck buttons. But the main issue is how do I get the controller itself to turn on without the cable and use it’s wireless capability? And yes, I’ve tested the batteries on another functional controller, they work fine.
Hi! You should open the controller. Clean the motherboard with isopropyl alcohol and clean the rubbers. Also, clean the buttons (if they are sticky, they could permanently press on the rubbers). Clean everything (make sure you clean it good). And after this, you should try again.
