Abstract: A vehicle speed, ambient temperature or surface-condition responsive wash system 89 has a control system configured to adapt the wash system's operation to sensed operating conditions. The adaptive system and method selectively controlling aimed windshield washer fluid sprays comprises a multi (e.g., two) mode system with a washer fluid driving pump 80 having an impeller 121 that is activated to supply fluid under pressure to a multi-mode nozzle assembly 98. Selectable first, or low pressure, and second, or high pressure, modes are provided by controlling the pump's polarity and impeller spin direction, hi an exemplary embodiment, a two-mode pump 80 is initially operated in the second mode, or reverse direction, producing a lower pressure flow.