I flip the switch nothing happens with water heater

[Twins]

Typically to turn on the hot water tank I flip a switch, a light turns on and you know its heating Here's the thing...I flip the switch and nothing happens. Just out of the blue it stopped working.
I've examined the breakers and fuses everything seems to be in order. I've even pressed the overheat reset button on the hot water tank itself. Still when I flip the "ON" switch nothing happens, not even the light turns.
I'm going to assume there may be an issue with the switch itself, however before I pull it apart and/or replace it, I'm hoping someone out there might have some insight. Is there something I'm missing?

Twins