Zanussi Dishwasher overheating

[plb]

I started a normal wash last night, and when I opened the dishwasher this morning the dishes were still boiling hot, way too hot to touch. Usually at the end of the drying cycle it should turn off and by the morning the dishes are cold. So it looks like the dishwasher kept heating the plates for the whole night. It happened once before a couple of weeks ago - and at that time something (I suspect the dishwasher) kept shorting.
The dishwasher is a Zanussi ZT 615.
As a minimum, this is consuming a massive amount of electricity... Any suggestion about what the problem might be and how to fix it?

Thanks!