Sometimes when you open the door it’s like the soap dispenser door just opened or it opened during the drying cycle. What are your thoughts?
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Replacement parts for PLD4375RFC3 models | AppliancePartsPros.com
Here is a tech sheet, it is for a RFC0 but is the closest I could find to your model.
http://manuals.frigidaire.com/prodinfo_pdf/Kinston/154580201en.pdf
Also here is a manual which may be useful though your unit is newer
http://frigidaireservicetips.com/pdfs/484_2.pdf
First I would remove the inner door cover and check that the connections between the dispenser and the control board are OK. Could be just a loose connection or a dirty connection.
If OK
Then it will be either the dispenser or the control board, since the problem is intermittent it is very hard to say which.
Check that the dispenser looks OK mechanically.
If you cannot find any problems then I would replace the dispenser as it is the more likely of the two.