A universal controller (16) for an electric motorized pump (18) having a mechanical switch (19) for turning on and off electrical power to the pump, and method of operation of same. The controller controls output pressure of the pump based on controlling the speed of the pump (for example by applying voltage over a greater portion of a duty cycle), so as to provide an optimal operating pressure derived from an automatically determined value for the pressure at which the mechanical switch opens and disrupts electrical power to the pump. It is manufactured as a standalone assembly, not attached to a pump. It can be operated so as to automatically seek and determine a switch-opening pressure for the switch (19), at which the pump pressure switch opens and so interrupts electrical power to the motor, and to then choose an operating pressure below the switch-opening pressure.