Hi @kenwoodsucks
What are the actual temperatures in the freezer and the refrigerator compartments?
Does the compressor stop running before the desired set temp is reached and then starts up again a bit later or is it running continually trying to reach the desired set temps but it never gets there? Usually with most refrigerators the set freezer temp is approx. -18°C (0°F) and the refrigerator is approx 3°C (37°F).
If it stops running well before these temps then most likely there's a problem with the temperature thermostat, (designated as Thermostat in the wiring diagram that you linked).
I also couldn't find much information on the model but if it is the thermostat you could try removing it and check what part number is printed on it and then search online for the part number to see if you can find suppliers
If it runs continually but the temps are never reached, then it could be a lack of refrigerant in the sealed system or a faulty compressor. Does the compressor get very hot?