What is indicated by flashing lights?

You replaced the heater without checking if it was faulty?

From a quick trawl of similar models, the fault you describe with these lights:

Wash = 1 - FLASHING
Drying = 2 - OFF
End = 3 FLASHING
Start/Pause = 4 - FLASHING

is Error 08, which seems to be a failed main board (or connections around it)

https://www.manualslib.com/manual/1230612/Indesit-Fdef31111.html?page=12#manual

http://www.ukwhitegoods.co.uk/help/fault-codes/dishwasher-fault-codes/3293-hotpoint-fdl-series-dishwasher-fault-codes

You could do well to contact one of those outfits for a more considered opinion.

acp
April 2017