Trailer Brake Control System

Systems and methods are provided for controlling operation of a trailer brake system associated with an agricultural vehicle-trailer combination. A coupling force between the vehicle and the trailer is determined and used to control operation of the trailer brake system in dependence thereon. A primary control strategy is used in dependence on the determined coupling force being within a coupling force range; and one or more secondary control strategies are used in dependence on the determined coupling force being outside of the coupling force range.