A method for finding an optimum trailer gain, comprising: applying trailer brake pulses to a trailer while a vehicle is coasting using a trailer brake of a trailer, wherein the trailer is coupled to the vehicle; monitoring an average deceleration of the vehicle and the trailer brake gain of the trailer brake pulses applied to the trailer while the vehicle is coasting; generating a graph of the average deceleration of the vehicle versus the trailer brake gain, wherein the graph includes a curve that illustrates a relationship between the average deceleration of the vehicle and the trailer brake gain of the trailer brake pulses applied to the trailer while the vehicle is coasting; and finding a bend point of the curve in the graph to determine an optimum trailer brake gain.