Ambient Light Hardware

Apple has confirmed all internal features of my iPad Air 2 are fine. They have concluded it is a hardware issue with the ambient light feature. Where is it located? Can it be cleaned? Is there self help repair instructions? Closest apple store is 2 hrs away. Best Buy can do it but their system is silly because they send it to apple for apple to send them parts. 🙄 The screen images and photos look almost like blurry X-rays.