GE refrigerator Model TFX20D Will not cool. Tested T-Stat, Defrost Timer and thermostat on coil. Still does not cool.

Probably low on refridgerant. Time to call a refridgeration engineer in.

Are you sure all of them went out? It's very unusual to lose all 3

Can only be tested cold and it should show resistant. or the defrost timer is not operating

Hi.

When the back of the freezer is icing up you need to test the defrost system, which is responsible for the problem . The evaporator coils freeze up because the defrost system is not working. this results in compressor and fan running most of the time and in reduced or no cooling, particularly in the fresh food section. The freezer may still be cooling.

Defrost system problems are quite a common issue with refrigerators. Coils freeze because of a defective defrost system. With coils frozen the condenser will go under stress and will loose efficiency. The result is the system not producing enough cold to refrigerate the fresh food section while the freezer section instead keeps working.

Try disconnecting power overnight. Allow the freezer to defrost with power off. If the fridge works after that you have a defective defrost system. In that case the problem may come back after a couple of days. To fix the problem the parts comprised in defrost system must be tested, so to find and replace the defective part.

The defrost system comprises defrost thermostat, heater, defrost control and fan. The parts that fail more commonly are thermostat and heater. Both parts are located behind freezer firewall and tested reading impedance with a multimeter. Element and thermostat are faulty if they return Ohms infinity (the circuit is open) when reading impedance with a multimeter at the part's contact.

If thermostat and element are OK, the next part to be tested is the fan. Fan can be tested by simply checking that the motor is running when energized.

Here a tip explaining how to deal with a similar problem on a different fridge model: Fridge not cooling. Procedure is similar with your model.

Here all parts and diagrams for your model.

You can also find parts and diagrams for most appliances using the links listed on this page: Where do I find parts and diagrams for my appliance?

Regards.

Ginko

Hi,

Check out these tips...they can help you figure out whats going wrong with yourrefrigerator and why it is not cooling

Refrigerator not Cooling or Fridge not Cooling

How to Defrost Refrigerator Defrost Timer Problem

Water Running in refrigerator from Freezer

Refrigerator or Freezer not Cooling or Getting Cold
heatman101

the defrost thermostat should be clamped onto the evap coils..defrost timer should be under fridge. If this is a newer model, it might have an ecm ( comp control) on top of the compressor..

If the evaporator coils behind the back panel of the freezer are icing up because of auto defrost failure that will stop the circulation of cold air and eventually affect the freezer too.

check defrost timer, defrost heater, defrost thermostat. In most newer models the timer has been replaced by an electronic control board. If the heater and thermostat are ok it’ll be the control.

You can turn the defrost timer till it clicks and everything shuts down. The heater should now come on. If it does, replace the timer. If it doesn't, check the heater and defrost thermostat. Turn the timer again till everything starts back up to end the defrost cycle.

Hi, If the defrost heater doesn't come on, check continuity on the bi-metal swtch located on the top of the evaporator coil. The bi-metal needs to be cold when testing it. If the switch is cold and shows an open circuit, it will need replaced. The bi-metal switch is a thermostat that turns the defrost heaters off when the desired tempurature is reached,.
Please let me know if this has helped you at all or if I can assist you further.

Thanks
Vic

Sounds like the defrost timer is not tracking the time properly. The unit needs to defrost once every 6-8 hrs. in order to work. Make sure the inside (evaporator) fan is running ok. If it rund for a few days and then warms up in the refrigerator section (coil iced), then the defrost timer is the culprit.

First point: The entire fridge is cooled by the freezer section. A fan blows air across to the food section.
2) Every 8 hours or so, a timer shuts off the compressor cycle, and starts up a heater to defrost the freezer coils. If the heater(s) are burnt out, or if the safety thermostat (to prevent overheating) is open, then you will have no defrost. The coils will frost up and eventually prevent airflow to the food section. Milk goes sour.
3) In rare circumstances, the timer itself can stall. This cause the same symptoms as above, but this is not as common as the other 2 causes of No Defrost.
Sequence: Check heater continuity. Check safety thermostat continuity while cold. Check defrost timer operation.
Hope this helps. I am a journeyman with 39 years exp. Happy New Year.