Demand Lamps
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
When the BCM is in not in battery saver mode, the interior light output is energized to provide voltage to the demand lamps.
The cargo and trailer assist lamps all illuminate with the cargo lamp switch (integrated into the headlamp switch).
The truck bed lamps all illuminate with the truck bed lamp switch located inside the LH rear of the truck bed.