Courtesy Lamp Circuit

The courtesy lamp circuit includes the courtesy lamps located under 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 on the roof rails adjacent to the rear outboard seating positions, the liftgate lamps located near each lower corner 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 ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) controls the output of battery voltage for the courtesy lamps in this circuit based upon hard wired inputs from the headlamp switch and electronic message inputs from the ignition switch (also known as the Keyless Ignition Node/KIN) and the Body Control Module (BCM).

After all of the ajar switch inputs to the BCM transition to open and the EMIC receives the appropriate electronic ajar switch status  messages from the BCM over the Controller Area Network (CAN) data bus, the EMIC will keep the courtesy lamps illuminated for about 30 seconds, then fade the lamps to OFF (theater dimming) over about 3 seconds. The EMIC also provides courtesy lamp operation based upon a resistor multiplexed input from the interior lighting thumbwheel on the headlamp switch, and provides an Illuminated Entry feature in response to certain electronic ignition switch status  message inputs received from the KIN and the Occupant Restraint Controller (ORC) over the CAN data bus. A resistor multiplexed courtesy lamp DEFEAT input from the interior lighting thumbwheel of the headlamp switch will cause the EMIC to override normal courtesy lamp operation.

The EMIC 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.