Steam controller stopped pairing to dongle

[laser0ride]

Hopefully this will help someone else. I was playing a game with my steam controller and walked away for a short break, and when I came back it wouldn't stay on, so I changed batteries, and it wouldn't connect to the dongle. Beep, flash for 15 seconds, beep, off. Opened settings and controller, general controller settings and tried Add a steam controller, but it wouldn't connect still. Tried recover firmware and it still wouldn't pair. With it wire connected I tried the support button in controller settings and it seemed to be fine. Noticed the firmware for Bluetooth was available to install for the controller so I installed that to the controller. That fixed the pairing to the dongle. Add a Steam Controller now paired with the controller and everything was back to normal. I don't need the Bluetooth option, but it seems pairing to the dongle now needs that firmware installed to the controller to work. I have no idea why the pairing was lost after a battery swap.

Steam menu>Settings>Controller>General Controller Settings(button)
With wired connected steam controller, click on the last button in the Controller Settings window, which should be "Detected Controllers:
Steam Controller"
The firmware install option for the newest Bluetooth FW will be under the support button, and above your controller firmware Version information. If you already have it installed, the button will read Rollback FW.
After upgrading the firmware, remove the USB cable and click the button "Add a Steam Controller" to pair to the dongle.

Hope that works for you, Game On!