blank screen fenix 5 S

You could try one of the following methods to reset the watch:

Hard-reset or Factory-reset Garmin watch – Option 1

• Use the menus: SETTINGS>SYSTEM>RESTORE DEFAULTS
• Garmin watch is factory reset and ready to pair to Garmin Connect again.

Hard-reset or Factory-reset Garmin watch – Option 2

• Hold the power/Light key until the menu appears.
• Choose power off.
• Press and Hold lap/Back button.
• Press the power/Light key
• You will get the menu “Clean user data: Yes/No?” release LAP button.
• Then choose yes to factory reset the Garmin watch
• Garmin watch is hard reset and ready to pair to Garmin Connect again.

Hard-reset or Factory-reset Garmin watch – Option 3

• Hold the power/Light key until the menu appears.
• Choose power off.
• Press and release power button and the watch should enter the boot sequence
• Press and hold the buttons the Start Button and the Back Button. once the Garmin logo appears
• Beep 1: release START button
• Beep 2: release BACK button
• Garmin watch is hard reset and ready to pair to Garmin Connect again.

Thanks for the reply and your help.

Unfortunately I can't actually try those because the screen doesn't work, so I can't see the menu or garmin logo or any of that stuff. I got in touch with garmin though and they are organising a replacement for me so all good.

Thanks again

I am having the same issue. Did you get a solution? 

I had to arrange a replacement through Garmin support, I wasn't able to get mine to turn back on. My replacement has been going great.