Disclosed herein are embodiments of systems for checking an electrical connection between a vehicle and a trailer. In one embodiment, a trailer light checking system for a vehicle comprises a plurality of exterior vehicle lights and a terminal connection configured to electrically connect each of the plurality of exterior vehicle lights to a respective trailer light. The trailer light checking system also comprises a lighting control system having a trailer connection checking mode configured to check the terminal connection by simulating manual operation of each of the plurality of exterior vehicle lights, such that a respective trailer light will actuate in combination with the simulated manual operation of each of the plurality of exterior vehicle lights if the terminal connection and the respective trailer light are functioning correctly.