Courtesy Lamp: Description and Operation

The second group include lamps that may be manually turned on by placing the interior lamp switch in the ON position, or by opening a door.
^ The Roof Rail/Reading Lamps
^ The Footwell Lamps
^ The Dome

The courtesy lamps, may be manually turned on by placing the interior lamp switch in the ON position, or by opening a door. When the ambient light sensor indicates a low light condition, the following scenarios will occur. When a front door is opened, the foot well, all door and the overhead console courtesy lamps turn on. If a rear door is opened, only the courtesy lights illuminate. After all the doors have been closed the courtesy lamps will remain illuminated approximately 25 seconds after the last door closes. When the ambient light sensor indicates daylight conditions, the interior courtesy lamps will not illuminate at all.

The INT LP fuse in the rear fuse block supplies battery positive voltage to the normally open switch contacts of the interior lamp relay. The INT LP fuse also supplies battery positive voltage to the interior lamp relay coil. The door modules communicate on a Simple Bus Interface (SBI). When you open any door, the switch contacts of the door jamb close. When a door open input is grounded, that door module sends a message to the Drivers Door Module (DDM) in order to indicate that a door is open. The DDM sends a class 2 message to the Rear Integration Module (RIM) in order to indicate which door is open. The RIM activates the interior lamp relay in order to provide battery positive voltage to the interior courtesy lamps. Depending on which doors are opened, front or rear, the proper interior courtesy lamps illuminate. The RIM provides a pulse width modulated ground to all interior courtesy lamps for the interior lights theater dimming feature. Some of the courtesy lamps are also used as reading lamps, each reading lamp may be manually turned on or off using it's own respective switch.

The courtesy lamps will normally turn off using the theater dimming feature. The courtesy lamps will also turn off immediately it an all door lock command is received with all the doors closed, or if the ignition switch is turned to either the ON or RUN position.