As the title implies, my fridge won't shut off, even when the control is set to the "off" position. I've removed the front panel and dropped the tray that holds the controls in place. If I slide the main control from the "off" position to the coldest position, I can hear a very slight click. How can I check to see if the thermostat is working? And, if the thermostat is working, is there another part that could be stuck, such as a relay?

I just replaced the thermostat. When I restored power to the fridge, it immediately went into defrost mode, which is exactly what it is supposed to do according to the service papers left with it. After a couple of minutes, the compressor kicked on. It seems to be fixed, but I'll find out in the morning.