I've tried the test cycle and it picks up a fault. It doesn't show the error but the light on the start button flashes 7 times.It looks like there may be a diagnostic mode on some Whirlpool dishwashers -- https://www.espares.co.uk/advice/careandmaintenance/whirlpool-dishwasher-error-fault-codes I don't know if that is applicable to your model.
You might want to attempt to use one of the "diagnostic mode" enablers -- https://removeandreplace.com/2016/03/09/whirlpool-dishwasher-error-codes-lights-blinking-flashing/