Abstract: An automatically controlled rear view mirror for a truck tractor-trailer rig is disclosed which utilizes an stranded metal cable running from an encoder box, mounted on the back center of a tractor to the front center of a trailer; whereby as the trailer turns, the angle between the tractor and trailer changes so as to change the length of the stranded metal cable; thereby triggering the encoder box to send digital signals to a control panel which controls the stepper motor located on the mirror assembly, thereby turning the mirror in response to the tractor being turned at an angle relative to the trailer.