Abstract: A vehicle rear vertical surface washing system comprising a horizontally movable carriage positionable within a frame adjacent the rear vertical surface of a vehicle and a vertically movable carriage which carries a rotary brush that washes and sweeps the rear vertical surface of the vehicle. Limit switches provide control signals to sequential logic implemented by relays and initiate the forward motion of the horizontal carriage toward the rear vertical surface of the vehicle at an appropriate point in the washing cycle. The light beam of an electric eye is broken when the carriage has moved adjacent the vertical surface, and provides a signal to halt the forward motion of the carriage. The rotary brush assembly mounted on the vertical carriage then travels downwardly washing and sweeping the vertical surface, and then reverses its direction and travels upwardly while rinsing and sweeping the vertical surface.