Hello, Have you tried setting the temperature controller to minimum? Please observe if the compressor at the back would shut off when you turn the thermostat control to its minimum.
If it does cut off, then I would say it is working but you could have set it too high. Counter clock wise is warmer and clock wise rotation of the controller is colder.
If it does not cut off, try to turn the dial all the way counter clock wise and observe if the compressor at the back would stop running. If it doea, then wait 10 minutes, turn the thermostat controller slowly clock wise until the compressor runs again. leave it to that setting.
If the compressor will not stop, then the thermostat controller is bad. You will need to replace it. Thank you.
I replaced the thermostat it is ok