The KZ and the ZN are not the same electrically but they are covered by the same manual. Kawasaki covers them within the same manual but there are major differences particularly when it comes to wiring. Coverage of the ZN is provided as a supplement in the back of the KZ manual including different wiring diagrams for each. The ZN features a "Junction Box" that combines fuses, relays etc into one housing. The KZ does not have a junction box.Don't look for ZN700 or ZN750. Look for KZ750 wiring diagram. ZN is just the marketing name for a cruiser style of the KZ750....or for the 700 for that matter, which was only debored briefly because political tariff related laws.
If I 'google' KZ750 wiring diagrams, they pop all over the place, even in color. Just make sure they are for the KZ750-4, not the twin which unfortunately had the same designation.