Courtesy Lamp Circuit

Courtesy Lamp Components

Power and Ground

The lamps in the courtesy lamp circuit are provided with a path to ground at all times.
The primary power feed for the courtesy lighting is supplied by a 9A Pulse-Width Modulated (PWM) high side driver located in the Body Control Module (BCM).

Courtesy Lamp Operation

The BCM controls the output of battery voltage for the courtesy lamps based upon hardwired inputs from the dimmer module and electronic message inputs from the Keyless Ignition Node (KIN) and the Radio Frequency Hub Module (RFHM).
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 status message inputs received from the KIN, the RFHM 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 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.