Re: Neff dishwasher
It depends obviously on the model and age, but if it is an old SMS type machine (heater visable inside) its more than likely to be the loom where it comes into the door, if so it may need a new loom/harness. Also check the door switch as they have a bit of a reputation for failing on the early ones.
If its a later one with the Instantanious water heater its less likely to be the loom, if its a later electronic type I would suspect a dry joint around the soldering to the transformer on the module.
Hope this Helps
Steve 😉