Backlight does not work when unplugged
Just received a used Lenovo T450s. Problem is, when the charging cable is disconnected, the backlight turns off completely, while plugged in, its fine.
Already wiped the laptop, ran through numerous bios and driver updates, but the issue remains.
I confirmed this is not a battery/power option within windows. I DO need to replace the external battery, as it doesn't seem to charge, but the internal one works great. Just curious if anyone has had this issue, and maybe knows a fix, before I go off replacing the screen/battery.