Have you replaced the dispenser box or only cleaned it out?
Is the water pressure entering the washer good?
Ok if the pressure is good and its a new water inlet and the box is fully clean then its looking like the control board is the fault.
As thats all thats involved in the softner section working. As to take the softner it brings both coils on a the same time and this diverts the water into the softner channel in the dispenser box. So with it being a new valve then we know thats working.
So its possibley not bringing both coils on at the same time. To test this to need a multi meter and set it going on a rinse cycle and the final rinse is when it takes the softner. Check both coils and see if they are working. If not then the control board is the fault.
If they are both working then its the dispenser. There will be a blockage somewere in the dispenser top. Now these dispensers you cannot split. So if you cannot clear it then you need to replace the dispenser unit and that will cure this fault.
So try the above and see what you find. As from what you say it will be either the control board or the dispenser box itself and you should be able to work out which it is if you have a multi meter to test it.
I see the question is still open. Do you still need help on this? If so then just get back to me.
If not then if you could remember to rate the answer that would be great.