The yellow light functions as the electronic steering damper warning indicator.
The light and warning symbol "ESD" go on if there is a malfunction in the electronic steering damper system.
However, this could also be caused by trouble with the charging system (e.g.
battery). If the warning light comes on, check the battery to be sure it is fully charged. If the battery is fully charged and the warning light still goes on, have the electronic steering damper system checked by an authorized Kawasaki dealer.
The electronic steering damper system maintains the last damping force setting if it fails.

A. Yellow Warning Indicator Light
B. Electronic Steering Damper Warning Symbol
KIBS Warning Indicator Light (For models equipped
with KIBS)
ABS Indicator Light (For models equipped with KIBS)ESD (Electronic Steering Damper) ECU Error (Service Code E3b, ZX1000JD/KD)
If this service code appears, check that the following parts
are correctly.
Crankshaft Sensor
Gear Position Switch
Starter Lockout Switch
Main Throttle Sensor
Rear Wheel Rotation Sensor
If these parts are normal, check the ESD ECU for its
ground and power supply (see ESD ECU Power Supply
...
Windshield
Windshield Removal
Remove:
Bolts [A] and Washers
Windshield [B]
Windshield Installation
Be sure to install the wellnuts [A] and the washers.
Tighten:
Torque - Windshield Mounting Bolts: 1.2 N·m (0.12 kgf·m,
11 in·lb)
...
Brake Disc Wear Inspection
Measure the thickness of each disc [A] at the point where
it has worn the most.
If the disc has worn past the service limit, replace it.
Measuring Area [B]
Brake Disc Thickness Standard:
Front 5.3 5.7 mm (0.21
0.22 in.)
Rear 4.8 5.2 mm (0.19
0.20 in.)
Service Limit:
Front 5. ...