Had the same problem when I purchased my 343 couple years ago. The control was totally corroded. I replaced it and it lasted about 18months before it rusted again. ( The frig stays powered up continuously). On the second replacement, I sprayed CRC anticorrosive liberally on the inside of the control and make a point to turn the knob once a month to keep it working. The replacement control knob / thermostat for my Isotherm frig costs approximately $75. You would think that the thing would at least last a few years.