The LED submersible square stop/tail/turn light is designed to conform to applicable US FMVSS108 and Canadian CMVSS safety standards for trailers under 80 in wide. This patented seven-function stop/turn/tail light with side marker light conveniently switches from functioning as a passenger side light to a driver side light seconds by snapping the side marker light into the corresponding slide channel. The life of a LED light far exceeds traditional incandescent lights and draws significantly less power than traditional halogen bulbs. The polycarbonate lens and housing are sonic welded to prevent moisture and corrosion. Additionally, all electronics are potted with water-resistant resin for a second layer of defense. This light is not only ideal for boat trailers, but for any utility, camping, snowmobile and motorcycle trailer where LED lights are desired.