Not the ON switch. I replaced the selector buttons (for Power Wash, Regular wash, Delicate wash and Rinse & Hold)
Again I suggest making sure the elctrical connection at the DW is firmly in place. This DW has a flow through water heater and a thermostat that won't allow the timer to advance if the temperature is too low. A weak connection can mean inadequate electrical power to the heater.
In regards to the water leak you may be interested in the following site. I am thinking of adding these units to my DW, clothes washer and water heater.... one mishap can cost much more than these units.
FloodStop - TheWaterAlarm.com