I have no voltage to the defrost heater during defrost cycle. The heater reads 95 ohms. The defrost thermostat reads open zero ohms. The heater fuse reads 80 ohms. Why no voltage? Where to look for fault? Thanks for your help!
Answer Hello George,
First off, the defrost thermostat should read continuity when it's below 50°F. Continuity is like touching the two meter leads directly to one another. Zero resistance. If this is what you meant in your statement, you need to replace the main control board. The evaporator thermistor can also be out of tolerance causing an issue.
There is also a heater in the fan shroud. This heater is bad. I checked it and there is no resistance. Could this cause the evaporator assembly to freeze as well? Also, should I change the thermistor, the coolant temp sensor and the circuit board?
Answer Hello Derek. The heater in the fan shroud is for the water tank. It should not cause the evaporator coils to freeze over. You will need to replace the evaporator. The new evaporator cones with new sensors as well. As for the other parts, if they are testing good, they should be fine. Hope this helps.