Abstract: A device and system are disclosed for trailer light diagnostics. The device includes, in one embodiment a housing, and a controller disposed within the housing and configured for wirelessly communicating a status of an electrical wire of a vehicle lighting system with a remote display, where the controller is electrically coupled with the wire. The system includes the device and the remote display configured for performing actions including establishing a wireless data connection with the trailer light diagnostic device, receiving, from the trailer light diagnostic device, data indicative of a electrical status of a wire in the trailer light system, and presenting, in response to the electrical status of the wire, a notification to a user.