A localized hydraulic circuit configuration detection and loading arrangement, and method, utilize a pattern of pins in an electrical interface connector that is unique to a particular hydraulically powered product delivery unit mounted on a self-propelled agricultural product applicator to close or leave open electrical circuits in solenoid operated pump control valve arrangements for selectively connecting a flow of hydraulic fluid at an operating pressure from one or more continuously operating pumps of the applicator to the product delivery unit, or for selectively bypassing the flow of fluid from one or more of the pumps back to a hydraulic reservoir of the applicator at a low, bypass pressure. When no product delivery unit is mounted on the applicator, the flows from all of the pumps are bypassed to the reservoir at the low, bypass pressure.