ford modeo 1.8zetec 5door 1999?

rear N/S door locked cannot be openedfrom outside or inside. the central locking system became U/S with electrical fault traced back to rear N/S door locking mechanism.disconnecting the umbilical cable to N/Srear door at central door pillar enabled central locking to be reactivated to N/Sfront and all other doors and boot lid.could the rear N/S C/Locking be activated via a separate umbilical connected to a slave battery without using or risking the the central locking circuits of the vehicle?(have got wiring diagrams to hand)