It very well could be. You can test continuity through the switch by connecting one lead to the light green, the other to the lower half of the switch housing. Push the button and check for continuity.
If the switch tests okay (I suspect it will, the switch is a pretty simple momentary contact switch) you will then either:
>Have to grind paint off the handlebars under the switch housing and under the handlebar clamp. Or....
>Run another ground wire from the switch housing to the frame or to a green/ground lead in the harness.