what manufacturer and model of fridge. does the flame stay lit when on gas. if the flame goes out it is your thermocouple, if the flame stays on the problem could be with the gas. can you have both elec and gas selected at same time, if so you may have boiled the condenser gas, if so its a fridge out job and turn it upside down for approx 1/2 hour to allow air lock out and gas to return to condenser.
sharky18, July 2008