I tend to think that there is a voltage drop of some kind. As mentioned above, trace electrical and clean connections.

 

hmm, gone to general tech 00 zx9, youll find all the info there you need to test the switches, hmm, the side stand ill have to take a minute to remember

 

i'm going to say that the neutral switch is probably gone though since the light doesn't come on at all.
should be an easy fix. a quick test would be pulling the connector off it and jumpering the connector. it the neutral light goes on then the switch is bad and the wiring is good.