If the light still works in the refrigerator then power is being applied to the unit.
It's not the cooling controls if you mean the levers where we adjust the coolness of the refrigerator and the freezer. We have them both maxed out and still nothing.
If the main cooling control/thermostat is defective I do not care how much you turn it up the unit will not run because the control is BAD and not allowing the signal to pass through to start the refrigeration system for the refrigerator.
A bad defrost timer/control board can stop the refrigerator from working IF it is stuck in the defrost mode OR the contacts are bad for the normal refrigeration operating circuit.
Sorry but there is NO magic bullet for this type of a problem. You have to use a electric meter to track down the offending circuit then take the corrective action be it replacing the defective part or correct the problem wiring.
Here is a pic of the wiring diagram for your unit