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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Transmission Assy Removal
Remove:
Engine Sprocket (see Engine Sprocket Removal in the
Final Drive chapter)
Gear Position Switch (see Gear Position Switch Removal
in the Electrical System chapter)
Collar [A]
O-ring [B]
Remove:
Clutch (see Clutch Removal in the Clutch chapter)
Shift Shaft Assembly ...
Rear Wheel Removal
Raise the rear wheel off the ground with the stand [A].
Remove:
Cotter Pin [A]
Rear Axle Nut [B]
Washer [C]
Rear Axle [D] (from Right Side)
Remove the rear wheel rotation sensor from the caliper
bracket (see Rear Wheel Rotation Sensor Removal in the
Brakes chapter).
...
Relay Circuit Inspection
Remove the relay box (see Relay Box Removal).
Check conductivity of the following numbered terminals
by connecting the hand tester and one 12 V battery to the
relay box as shown in the figure (see Relay Box Internal
Circuit in this section).
If the tester does not read as specified, re ...