At the top of the door where there are labels regarding the dishwasher, you find "GE Profile" followed by three model numbers: GSD1930TWW, GSD1920TBB and GSD1910TAA. Those are the only numbers I found aside from the part number for the door itself.
Thank you. I will try your suggestions. Hoping it is just a small fix so I don't have to get a whole new dishwasher. But at 18 years old, I am sure "old reliable" is very near the end of its life.