A tractor controller for controlling trailer brake applications comprises an input for receiving a signal indicative of a trailer brake application and control logic. The control logic receives a signal indicating a trailer brake application is requested, compares the trailer brake signal to a predetermined signal profile, applies the trailer service brakes in response to the trailer brake signal meeting the signal profile and compares a duration of the trailer brake signal to first predetermined time. A warning is provided in response to the duration of the trailer brake signal being greater than a first predetermined time and the control logic discontinues the trailer service brake application in response to duration of trailer brake signal being greater than the second predetermined time.