Convenience lights
Most cars have at least one dome light (UK, courtesy light) located in or near the ceiling of the passenger compartment, to provide illumination by which to fasten seatbelts and enter or exit the car. These often have an option to switch on when the front (or all) passenger doors are opened. Many vehicles have expanded this feature, causing the overhead interior light to remain on after all doors are closed, allowing passengers to fasten seat belts with added illumination. The extended lighting cycle usually ends when the vehicles ignition has begun, or a gradual reduction in light emitted after a couple of minutes if the car isn’t started, called “theater” lighting. Interior lighting has been added on some vehicles at the bottom edge of the dashboard, which illuminate the floor for front passengers, or underneath the front seats at the rear, to illuminate the floor for rear seat passengers. This type of convenience lighting approach is also sometimes used to illuminate interior or exterior door handles, exterior step running boards, or electric window switches.
LED light sources are beginning to appear increasingly as interior convenience lights in various locations as the technology becomes more widely used, especially with finely focussed lighting on console control surfaces and in cabin storage areas.
There may be additional map lights that are aimed at specific passenger positions, that allow for reading without particular glare distraction to the driver. Some vehicles have approach lighting (puddle lights) integrated into the exterior mirrors or lower edges of the doors, as well as activating interior lighting, that is activated via key fob. Many cars have lights in the trunk (or boot), the engine compartment, and the glovebox and other storage compartments.
Most instruments and controls on a dashboard in modern vehicles are illuminated in some fashion when the headlamps are turned on, and the intensity of light can be adjusted by the driver for comfort. Saabs feature an aerospace technologies-derived “night panel” function which shuts off all interior illumination save for the speedometer (unless attention is called to a critical situation on another gauge) to improve the driver’s night vision.