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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Front Fork Oil Change
Remove the front fork (see Front Fork Removal (Each
Fork Leg)).
Turn the spring preload adjuster fully counterclockwise for
removing the piston rod assy easily.
Hold the inner tube lower end in a vise.
Using the wrench [A], unscrew the top plug [B] out of the
outer tube.
Special Too ...
Special Tools and Sealant
Compression Gauge, 20 kgf/cm²:
57001-221
Valve Spring Compressor Assembly:
57001-241
Valve Spring Compressor Adapter,
25:
57001-1019
Valve Seat Cutter, 45° - 27.5:
57001-1114
Valve Seat Cutter, 45° - 32:
57001-1115
Valve Seat Cutter, 32° - 28:
57001-1119
Valve Seat Cutter ...
Premuffler Chamber Removal
Remove:
Muffler Body (see Muffler Body Removal)
Right Lower Fairing (see Lower Fairing Removal in the
Frame chapter)
Front Seat (see Front Seat Removal in the Frame chapter)
Oxygen Sensor (Equipped Models) (see Oxygen Sensor
Removal (Equipped Models) in the Electrical System
chapter ...