Thanks for that.
It really sounds, from what you've posted, that the dispenser is faulty.
You would need to obtain and fit a new dispenser to try and cure the fault.
There are only the dispenser, wiring and main control board involved.
If you have, and can use, a multimeter, unplug the appliance and take the outer door off.
Check the dispenser to see if it's open circuit and test to see if it's being powered during the wash. (you'll need to restore power to check this).
If it's being powered or if it's open circuit, it confirms the dispenser is the faulty item.
It it's not being powered, it suggests the control board is faulty.
Check it out, see what you find and get back to me if you need more help
Hope this helps