Also, a heads up.. mine did the same thing so I bought a new switch before I tried to troubleshoot the old one. There's a piston like appendage in the end of the switch that gets pulled by a spring that actuates the light. Mine was rusty, so I cleaned it with some fine grit sandpaper and it works like new now
So... I have a brand spankin new switch if you end up needing one.

So... I have a brand spankin new switch if you end up needing one.