DX302 not heating ?

My DX302 dishwasher isn't heating . I think it maybe the pressure switch in series with it .After removing it and testing it . It seems to work after that .A trip to the appliance spares place to find out that there is 2 of these but need to know if it's item 51 or 52 on parts list . Or is it the same problem as everyone else seems to be having with the circuit board if so how do I access it . thanks

Sean
April 2012