an interior lighting system for an automotive vehicle has an upper group of lights mounted in the vehicle interior , a lower group of lights mounted in the vehicle interior , and a switch mounted in the vehicle interior . the switch is movable between the dome position in which both the upper and lower groups of lights are illuminated , a dim position in which both the upper and lower groups of lights are illuminated between a maximum and a minimum intensity , a floor position in which only the lower lights are illuminated , and an off position in which neither the upper nor the lower group of lights are illuminated . the lower group of lights are illuminated when the switch is in the floor position after a door - ajar condition is sensed and the vehicle is moving at a predetermined velocity . additionally , when the switch is in the dim position , the upper and lower groups of lights are illuminated only when a door - ajar condition is sensed and the vehicle is moving at a predetermined velocity .