Abstract: A trailer brake controller for controlling a towed trailer braking system through the use of an independent processor mounted for communication between a towing vehicle braking system and a towed trailer braking system. The brake controller receives a signal indicative of the brake pressure applied by a user and relays the signal to the processor for processing and communication to the towed trailer braking system. A visual display positioned within visual range of the user allows the user to observe the status of the brake controller operations and adjust the output signal where necessary. A manual override allows the user to override the output signal generated by the controller and apply full braking power of the trailer to stop the trailer and the vehicle. A number of automatic overrides facilitate smooth operation of the brake controller by detecting abnormal conditions in the system connections and relaying the diagnosed conditions to the processor.