Thermostat wiring?

Hello,
I have a faulty fridge/freezer thermostat. I 've taken off all the spade-end attached wiring clips, but one final one remains that is somehow different. It looks like a small metal tube about 2mm in diameter that goes into the thermostat itself and at the other end vanishes with all the rest of the wiring into the back of the fridge with seemingly no visible way of detaching it at the thermostat end, other than trying to open the thermostat. Is this necessary, or is there another way of doing this? Thanks for any help I can get. Peter