AEG Favorit 911936627/04 not heating but element is fine

Last week we noticed our dishes coming out the dishwasher soaking and not very clean and further investigation showed the water was not heating. I made an assumption that the element must have burnt out and ordered a new one. I took the thing apart yesterday and tested the resistances across the new and old and they were the same (c26 Ohms), leading me to the conclusion that the existing one was in fact ok. I fitted the new anyway and sure enough no difference.

I am domestic heating engineer so used to fault finding on boilers but was very confused by the fact that when connected the element was 240v both sides (unlike an immersion for example), and then noticed the drain pump was the same but when running it was normal (ie no volts) on the blue neutral terminal so am I right in thinking this dishwasher switches on the neutral (not something I have come across on a boiler, hence my surprise!)? I then noticed that the thermostat has all blue wires coming out of it and wondered if there was a connection with the neutral to the heater as this is the next obvious thing that would stop the element from being switched on? If the dishwasher switches on neutral this would seem to rule out some sort of neutral fault on the wiring (though I have had to repair the harness where it comes under the door as some of these wires had worn but this was indicated by a loss of power as you opened the door). I’d be grateful for any tips on further testing that might be worth doing, having spent £30 on a new element I’m keen not to chuck another part at the problem unnecessarily! Thanks in anticipation.

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