A boat trailer has a plurality of light sources housed within a sealed enclosure. The sources are electrically connected to a towing vehicle's lighting system and optically coupled through light condensing means to fiber-optic connecting fittings. Electrical circuitry for light source emitting elements is disposed within the enclosure and a multi-conductor electrical bulk-head connector is on the enclosure. A plurality of fiber-optic cables have environmentally securing end connectors. Fiber-optic cable tap devices function to extract a specific percentage of the light transmitted through a fiber-optic cable to a side outlet for distribution among a plurality of emitting apertures performing similar lighting functions. Light emitting apertures with light diffusion and control from the entering beam to the full area of the light emitting aperture is accomplished through lenses and/or critical angle reflectors.