Its a lighting kit that are on the newer Ford's that allows you to do accent lighting in the interior of the car. There is lights that light up the floor boards of the car and also a light that lights up the cupholders
I'm trying to find out if the Ambient Light accessory is the same as the factory Ambient Lighting Package.
Now that I look at the accessory kit, I don't think that it is. On our Fusion, the illuminated cupholders look like they're integrated into the center console, and I can't see how that would work with an add-on kit. And instead of the foot-well "light bars" of the accessory kit (which has no pictures that I can find), each foot well in our Fusion is lighted by a single tri-color LED, aimed downward.