A system (100) and method (900) for illuminating the interior space (90) of a trailer (84). The system (100) can utilize a power box (200) to draw and store electricity from a tractor (82) and use that electricity to activate LED assemblies (300) within the trailer (84) is untethered from the tractor (82). The lights (310) can be activated by a motion sensor (340) associated with the location of the lights (310) being activated.