Soap dispenser wont open

I bought a Fridgidaire dishwasher about 18 months ago and it has worked well until now. Suddenly the soap dispenser wouldnt open during the wash cycle. I have been opening the dishwasher during the cycle to release the dispenser. Someone came by and replaced the dispenser but it still is not working. Does anyone know what the problem could be?

Here are your parts
Replacement parts for GLD2250RDB5 models | AppliancePartsPros.com

Here is the tech sheet
http://manuals.frigidaire.com/prodinfo_pdf/Kinston/154526501.pdf

And a manual
http://frigidaireservicetips.com/pdfs/484_2.pdf

Try running the diagnostics. If it opens then you have a control board problem.

Then I would check the replacement dispenser just to be sure it is OK see page 42 in the service manual.

Next check the wires from the dispenser to the control board for continuity.

If all OK then the most likely culprit is the control board.