I replaced my Water Heater Switch but it was located in the back of the WH and so inaccessible that I had to pull the entire unit. Also found some fried wiring.
The switch should just pop out (as I remember it just snaps in and is held in place with plastic `ears') but you may destroy it in the process. To bypass the switch just connect the two wires that go to the switch. But, be sure it is a switch problem. You should have voltage on one side of the switch and either voltage or no voltage on the other side depending on whether the switch is on or off respectively.