I actually ran into this same problem yesterday. No PIN when pairing. No blue light for wireless connection. I tried everything written here including manual update, update via Quik, WiFi Reset, battery removal, and contacting support. But nothing happened. Camera's WiFi is still dead.
However, my camera's wireless magically came back to life just minutes ago. I've read somewhere else that I can use Nearby Device Scanning (Android Settings) to wake up the camera using Bluetooth Low Energy. Right from the day I first used my phone, I have disabled Nearby Device Scanning. So I turned on Nearby Device Scanning in my Android Settings. On the GoPro App, I attempted the device pairing with Bluetooth and WiFi on. On the camera, I go to Setup > Pair > GoPro App.
I don't know if Nearby Device Scanning is the real answer to this issue. But I hope it would work for you as well.
