The auto illumination feature means when you connect the kit to a switched power source (headlight fuse, door pin, dome light, etc), once that location gets power the kit will automatically come on. For example, if you connect the kit to the door pin and activate the auto illumination, every time you open your door the kit will power on and illuminate. Once you shut your door the kit will shut off. Please note with Auto Illumination Mode, the kit will then turn on and off with that source only. You will not be able to control the kit independently other than this function.