An electrical connector includes a housing having a cavity and a wafer stack received in the cavity. The wafer stack includes a plurality of electrical wafers arranged parallel to each other within the cavity. Each wafer includes a dielectric body and a leadframe having plural conductors held in the dielectric body, the conductors having terminating contacts and mating contacts with leads therebetween. The terminating contacts are both horizontally staged and vertically staged and exposed in a pocket of the dielectric body for electrical termination. The mating contacts being exposed for electrical connection. The electrical connector includes a flex harness includes a plurality of FPCBs. The FPCBs are electrically connected to corresponding wafers. Each FPCB has a stepped mating interface with conductors along the stepped mating interface configured to be electrically connected to corresponding terminating contacts.