Courtesy Lamp Circuit
The courtesy lamp circuit may include the courtesy lamps below each outboard end of the instrument panel and, depending upon the selected vehicle options may include either the dome or map and reading lamps located in the overhead console near the windshield and in the headliner over the second and optional third row seating positions, the liftgate lamp located near the center of the liftgate trim panel, the glove box lamp in the top of the glove box opening in the instrument panel and the vanity lamps located in the sun visors.
The lamps in the courtesy lamp circuit are provided with a path to ground at all times. The Body Control Module (BCM) (also known as the Common Body Controller/CBC) controls the output of battery voltage for the courtesy lamps in this circuit based upon hard wired inputs from the dimmer module and electronic message inputs from the ignition switch (also known as the Keyless Ignition Node/KIN) and the Radio Frequency (RF) Hub.
After all of the ajar switch inputs to the BCM transition to open, the BCM will keep the courtesy lamps illuminated for about 30 seconds, then fade the lamps to OFF (theater dimming) over about 3 seconds. The BCM also provides courtesy lamp operation based upon a resistor multiplexed input from the interior lighting thumbwheel of the dimmer module, and provides an Illuminated Entry feature in response to certain electronic ignition switch status message inputs received from the KIN, the RF Hub and the Occupant Restraint Controller (ORC) over the CAN data bus. A courtesy lamp DEFEAT mode input based upon a resistor multiplexed input from the interior lighting thumbwheel of the dimmer module thumbwheel will cause the BCM to override normal courtesy lamp operation.
The BCM provides a battery saver (load shedding) feature for all courtesy lamps, which will automatically turn these lamps OFF if they are left ON for more than about 10 minutes after the electronic ignition switch status message transitions to OFF. If any courtesy lamp input is received subsequent to a 10 minute load shed and prior to a new ignition cycle, the courtesy lamps will turn OFF after 90 seconds.