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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)DFI System
1. ECU
2. Battery
3. Vehicle-down Sensor
4. Exhaust Butterfly Valve Actuator
5. Vacuum Chamber (Other than US, CA and CAL Models)
6. Air Intake Valve Actuator (Other than US, CA and CAL Models)
7. Air Intake Valve (Other than US, CA and CAL Models)
8. Air Flow
9. Air Intake Solenoid Valve ...
Meter Unit Removal/Installation
Remove the upper fairing assembly (see Upper Fairing
Assembly Removal in the Frame chapter)
Remove the bolt [A] (other than US, CA and CALmodels).
Slide back the dust cover and disconnect the meter unit
connector [B].
Remove:
Bolts [A]
Nut [B] (other than US, CA and CAL mode ...
Liquid Gasket, Non-permanent Locking Agent
For applications that require Liquid Gasket or a
Non-permanent Locking Agent, clean the surfaces so
that no oil residue remains before applying liquid gasket or
non-permanent locking agent. Do not apply them excessively.
Excessive application can clog oil passages and
cause serious damage.
...