Jose for Model Number ZISB48DYB There are two thermostats attached to the back of the evaporator coils but the parts diagram only references one. The upper one has a blue wire that goes to the fan and a red wire that exits the freezer compartment but I can't tell where it goes, so can't test it for continuity. The lower thermostat has an orange wire that goes to the deicing tray/pan and a pink wire that lead to the icemaker fill tube heater. It shows continuity with a multimeter. What do each of these thermostats do? Where does the red wire go? Are both thermostats the same? When the defrost timer is advanced manually (appears to work fine) the defrost heater works and the deicing pan heats. Why might ice form on fan and build up thick next to evaporator coils? Thanks
Answer Jose, the orange and pink wired thermostat would be the defrost heater and fill tube thermostat WR50X45 and is utilized to prevent overheating. The red wire on the other thermostat would go to the defrost timer and it is used to prevent the fan from turning on unless the evaporator is cold enough and it would be the same as the heater thermostat. A thick build-up of ice on the evaporator coil is commonly caused by a defrost failure, either from the heater WR51X322, thermostat, or defrost timer WR9X502 failing. If it builds up enough, the ice will also accumulate on the fan. Read More... Answered by AppliancePartsPros.com | Sunday, May 8, 2022