Dishes don't dry and mold and scum in bottom and around bottom gaskets

The dishes do not dry and there is not much heat coming out when we open the door after the wash is complete. We have checked the continuity of the heating element and it was ok but it doesn’t seem to be heating. We were thinking that maybe the heater thermostat might be the next thing to check. We are tired of all the mold that appears inside on the filter and even along the bottom of the door gasket. Dishes also come out with a greasy residue on some of them. About ready to just go buy a new one but hate to spend the money when this one is not that old

Here are your parts.
You will have to choose the correct unit in the Matching Model Numbers section
Parts for FGHD2455 - AppliancePartsPros.com

See the attachment for the tech sheet.

Yes check the hi-limit thermostat.

IF OK then check the heater circuit at the control board just to be sure it is not a bad wire or connection
If OK
Then odds are that the control board is bad.

We are pretty sure that the heater has never worked in the dishwasher. We have opened it up to look at the control panel and find this one wire is smashed on the ribbon cable coming from the front control panel that leads to the other control panel. Do you think it is enough to cause it to not function or is it too hard to tell.

I cannot really tell.
You will have to check it with a meter.