GM Genuine Parts Trailer Brake Controls are designed, engineered, and tested to rigorous standards, and are backed by General Motors. the brake controls signal a trailer's brake system when the driver presses on the brake pedal and adjusts how much braking power is needed to stop the trailer. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).