Which of the following is the order of the four steps for testing your trailer's service brakes ?
Check normal air pressure. Release the parking brake. Apply the trailer brakes, using manual control if equipped. Stop braking and pull forward slowly.
Check normal air pressure. Release the parking brake. Pull forward slowly. Apply the trailer brakes, using manual control if equipped.
Apply the trailer brakes, using manual control if equipped. Release the trailer parking brake. Check normal air pressure. Pull forward slowly.