Our dishwasher started making a humming noise when started and when it was done the soap block was lying intact in the bottom. I ran the test and it immediately showed "heater fault"

I took out the control board and I couldn't find any burned spots under the relay. everything looked ok.

I started a cycle and measured the current. It never exceeded 1.1 amps and what little water in the unit was cold. From my reading the heater, high limit or flow switch could be bad and I need to check the resistance of each. To do this I need to remove or block the tank.

First, am I on the right track or should I go ahead and replace the control board?

How exactly do I get to the heater, high limit and flow switch and what do they look like? I have the dishwasher pulled out of its hole but still connected.

Thanks,

Don