Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionCheck 3-6: Neutral Indicator Light (LED) Inspection
Connect the leads in the same circuit as Check 3-2.
Connect the terminal [8] to the battery (–) terminal.
Check that the neutral indicator light (LED) [A] goes on.
If the indicator light does not go on, replace the meter unit.
...
KIBS System Circuit
1. Ignition Switch
2. Front Wheel Rotation Sensor
3. Front Brake Light Switch
4. Joint Connector C
5. Joint Connector D
6. ECU
7. Rear Wheel Rotation Sensor
8. Rear Brake Light Switch
9. Battery 12 V 8.6 Ah
10. Main Fuse 30 A
11. KIBS Motor Relay Fuse 30 A
12. KIBS Solenoid Valve Rela ...
Gear Position Switch Inspection
NOTE
Be sure the transmission and external shift mechanism
are good condition.
Remove the fuel tank (see Fuel Tank Removal in the Fuel
System (DFI) chapter).
Disconnect the connector [A].
Set the hand tester [A] to the × 1 kΩ or × 100 Ω range
and connect i ...