1997 Cadillac Seville Owner's Manual - Page 110

The light sensor for theDRL and the twilight sentinel is located in the center of the front defogger grille, you If cover the sensor. it will read "dark" and the lamps will come on. Cluster lighting as well as instrument panel lighting automatically dims when it becomes dark outside. When it's dark. the brightness control can be manually acljustecl. Cluster lighting and instrument panel lighting auton-iaticallv brighten when it becomes light outside.