First I changed the bulb when I got it,then took it apart and cleaned it.I put new batteries in.....nothing.The switch was very loose as though it wasn't making any contact inside.Thats as far as I got.I hope I explained myself correctly.
I'm not sure what might be required to fix it but to be honest it might not be worth the effort depending on whats wrong and how difficult finding a switch is. Just my 2 cents