where is the thermostat/heat sensor in my Bosch Classixx dishwasher located?

I have a problem with my Bosch Classixx dishwasher.
It pumps the cold water in and the programme goes no further,i can then bypass the programme and the water will pump out.
This (i think) tells me that either the programme card /the heating element or the thermostat is u.s.
I've had the card out ad it looks good i.e. no burn marks to show a breakdown.
Also the heater element checks out electrically i.e. no short to earth etc.
That leaves me to think that the thermostat/heater switch is u.s. but i dont know where it is located,is it built in to the heater element and if so are they supplied as one unit or seperately?
Can anyone please help?