Stuck in wash cycle

I have a Whirlpool dishwasher that stays in the wash cycle and will not advance. It eventually needs to be shut off/cancelled. I was told a possible bad thermostat. If so can someone help locate and how to test/replace this part(s)? Thank you!

You should probably start by putting the machine in a service mode.remove the lower kickplate and behind that will be instructions on how to do it. see if it passes the test you can put an amp probe on the orange wire coming off thermastat thats wired in series with the heater if it draws amperage then the heater and stats are ok on that would only leave the board thats bad