An auxiliary hydraulic system for vehicles, in particular pick-up trucks, is configured to supply hydraulic fluid under pressure to both on-board and off-board auxiliary equipment such as snow plows, dump boxes and wood splitters. The auxiliary hydraulic system includes a multi-piston fluid pump with electrically selectable poppet valves and an associated microprocessor control that facilitates variable output so that a desired proportional flow can be supplied to the auxiliary equipment. The system also provides a switchable valve arrangement for directional control and an arrangement of fluid distribution pipes and detachable couplings so that a range of different auxiliary equipment can be quickly and simply connected to the system. A simple user interface is also included so that the operator can command the auxiliary equipment from either within or in close proximity to the vehicle.