Well making a new Google Account for this doesn't make sense. Also, the person before had the same Google Account on another phone and the notifications were lit up perfectly on the person's previous phone. Anyways, I DOUBT this has ANYTHING to do with, for example, WhatsApp, notifications.
It sounds odd because by defect it IS activated so why would it be deactivated? Also, with the widget and the light manager app it does not light up either.
There was to be some strange software bug in MIUI playing up here.
Fortunately there's a simple fix for this issue, and it's one that apparently applies to Motorola and some other phones too...
Motorola has released a widget that lets you toggle the notification light on and off, so if you're affected by this bug simply download it, place it on a home screen and toggle it on. After that you can remove the widget and your notification light will continue to work.
I dont know why but this bug comes with old google acc.
My LED was dead(it was on only on charging and batery low,not for notification),and I did factory reset,create new google acc. installed Notification light widget,and LED started to work,then I installed a Light manager for editing colours for notification.
Strange but black G630 have this bug,white G630 LED works perfectly.