Courtesy Lamp: Description and Operation

Battery voltage is applied at all times through fuse 34 to the foot well light, ignition key light, and the entry light timer circuit in the integrated control unit. When you open the driver's door, its door switch closes and grounds the door switch input of the entry light timer circuit. The timer circuit then turns ON the foot well light and the ignition key light. The timer circuit keeps the lights ON for several seconds after you close the door (driver's door switch opens).