The Ambient Light Sensor is an automatic feature designed to balance battery life, with optimal display brightness. It does this by detecting the light present in the laptops environment and adjusting the display accordingly. While battery life is increased, there are situations where manually controlling the brightness is desirable.
Anyone familiar with the older location for enabling and disabling the ambient light sensor discovers it all changed in Windows 8.1. Older utilities designed to incorporate the ambient light sensor interface were retired when we went to Windows 8.1. (For Example: Quickset or Backlitkb.exe)
The steps to disable the ambient light sensor in Windows 8.1 are listed below:
Press the Windows + X key to open the quick jump menu. Click or tap Power Options.
In Power Options, Click or tap Change plan settings (hyperlink on the right side) for whatever plan you are using.
Click or tap Change advanced power settings.
Scroll down to the Display section, click, or tap the + in front of Display and Enable adaptive brightness.
Choose Off for whichever power situation that you want to control manually (battery or AC), or both.
Click or tap and OK to save and close. Then close any remaining open windows.
On laptops equipped with Intel Display Power Saving Technology (DPST), you must complete these additional steps:
Right click on the battery icon that is in the system tray.
Click Dell Extended Battery Options from the menu.
Under Dell Intelligent Display, click on Configuration and turn this feature off.