This Brake Circuit Disconnect will prevent brake signal override on the towed vehicle. In some vehicles, when a braking system is installed which activates the towed vehicles brake, it causes the towed vehicle to send another brake signal to the towed vehicles tail lights which in many cases can cause the signal being sent from the coach to be over-ridden or canceled out. This creates a problem if you should have your turn signal engaged in the motor home and the brake signal being sent from the towed vehicle is over-riding the motor homes signal, thus making the travelers behind you unaware that you are preparing to make a turn. This part is not needed for every tow vehicle. Contact us and we can inform you if we have any specific notes on your vehicle.