An EESS is not a PCB...
You have a PCB, the newer models are computerized. They are called EESS.
Temperature Control Unit (?) is the device that looks at engine temps to identify if glow plugs need to be activated.
An EESS works differently from a PCB, and does more internally. That is what RWH was referring to.
Bottom line is that you need a new box and a new temp control unit. RWH prefers newer EESS models. You would need to buy one of those with the matching temp sender unit.
I think you should contact a site sponsor and member like 86HUMV for parts so he can clue you in.
You can also google and then call the store called Kascar if 86HUMV is not around.
You need to explain that you have a KDS green box that you need to upgrade to an EESS with matching temp sensor.
Be prepared to give away the better part of $900