Dishwasher not heating

[frying_pan_cat]

My dishwasher seems to have stopped heating, the water always seems to be cold and it keeps flashing when it finishes. It also seemed to run all night the other night non stop rather than stopping automatically but hasn't done that since.

It's a built in dishwasher and I can't find any identifying marks on it so can't google for a user manual. Does anyone have any tips for either finding out what it is or how to start fault finding. I can post some pics if that'll help

Thanks

 

[frying_pan_cat]

Definitely not under warranty. Any idea where I would start looking to find the model number?