If the display function does not work, replace the meter unit.

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Clutch Lever Installation
Install the clutch lever so that the mating surface [A] of the
clutch lever clamp is aligned with the punch mark [B] of
the handlebar.
Tighten the upper clamp bolt first, and then the lower
clamp bolt.
Torque - Clutch Lever Clamp Bolts: 7.8 N·m (0.80 kgf·m, 69
in·lb)
There will be ...
Subthrottle Valve Actuator Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Disconnect the subthrottle valve actuator connector and
connect the measuring adapter [A] between these connectors
as shown in the figure.
Main Harness [B]
Subthrottle Valve Actuator [C]
Special Tool ...
Terminal Numbers of ECU Connectors
1. Subthrottle Valve Actuator: Y/BK
2. Subthrottle Valve Actuator: BK/O
3. Unused
4. Front Wheel Rotation Sensor Signal: G/Y
5. Unused
6. Starter Lockout Switch: R/G
7. Gear Position Switch: G/R
8. Crankshaft Sensor (–): BK
9. Power Supply to Sensors: BL
10. Unused
11. Intake Air Pre ...