Hi @Laura Demma
Here’s the [https://f01.justanswer.com/smitty1486/9190289f-8e09-4296-92bc-9e5bef5848cb_WDT790SAYM_Tech_Sheet.pdf|tech sheet] for your model.[br]
Here’s what it says about entering the Service Diagnostics:
To invoke the Diagnostics Cycle, perform the following while in standby:
■Press any 3 keys in the sequence 1-2-3-1-2-3-1-2-3 with no more than 1 second between key presses.
■The Service Diagnostics Cycle will start when the door is closed.
■To rapid advance 1 interval at a time, press the Start/Resume key. Rapid advance may skip sensor checks as some checks require 2 complete intervals.
Hopefully they will help you try find out what’s wrong.