Sounds like you have a pluged defrost drain. Look in the fridge section at the back, there is a vent where cold air comes out ,behind it is a small cup where water flows through to a defrost pan. make sure this cup is clear. Then check the back of the fridge where the drain tube and trap is at make sure this is clear to the defrost pan. Now for the smoke[lol] i hope this is only fog or cold air coming out of the fridge..