Ice forming on rear of freezer wall

• One cause of this is the compressor is going bad or Freon is low. The freezer is no longer able to achieve the zero temperature requiring the compressor to run continually. The refrigerator because of the continues running begins to freeze up. Food in the refrigerator begins to freeze and the freezer is not as cold as it should. This results in a very expensive repair of replacement of the unit .
• The defrost cycle is not working. Depending on the conditions the unit has a sensor that detects when the defrost cycle should initiate. If this fails to occur than ice builds up on the coils and air can no longer pass preventing the normal cooling process. Many models use a mechanical timer that stops. On some units the defrost cycle can be initiated via advancing the mechanical timer. This repair is a reasonable expense.
• The third possibility is a door was left open and the unit iced up the cooling coils. Suggest in that case shut off the unit , remove the food and allow the unit to manually defrost, Restart and see if unit gets cold and defrost cycle is working.

u seem to have a defrost issue? check ur defrost terminator and ur defrost timer, it seems like its not going into defrost cycle, you can manually set defrost timer by using a flat head screw driver look under the timer which should be at middle top of fridge usually. you will see a small hole around the center area. place the small flat head into it and catch the grooves and turn slowly till you hear a click that should then turn on ur defrost cycle, if it does you need to replace timer, of course u can always do this every 8 hours until replacing it. if nothing happens after turning it then check the defrost terminator more than likely bad? may also want to check thermistors

The reason your refrigerator will not cycle off is because it cannot satisfy the thermostat because ice is blocking air flow across evaporator inside the back wall of your freezer. I want you to look for a small hole inside the control panel where you can place a flathead screwdriver and slowly turn the timer clockwise until compressor and fans stop. If there is no hole there you will need to lower the control panel inside the fresh food compartment. Here is your replacement defrost timer should it turn out to not be good=> 2314156 Defrost Timer

Once the compressor and fans stop I want you to wait up to 30 minutes to see if the compressor and fans restart. If they do not restart on their own simply turn clockwise again until they do. Doing this will test the timer and cause the freezer to go into defrost. If defrost does not work this way and ice buildup remains on the rear wall of freezer we will need to remove the rear panel in freezer and manually defrost the evaporator with a hair drier. This way we will be able to inspect the=> W10140847 Defrost Heater Assembly

Also found here=> W10140847 Defrost Heater Assembly
and defrost thermostat=> 2321800 Defrost Thermostat I will be here should you have questions, Thanks Sea Breeze

Defrost problem: 3 components. Defrost Heater. Timer (circuit board or motorized) & Thermostat.
Remove cover on the inside back wall (usually 6 screws). Note frost pattern. (bottom of evaporator coil)
Put refrigerator into defrost cycle and note the defrost heater come on, or not. (careful heater can glow red hot)... Unplug Frige and test defrost components. Replace bad component... Refrigerator should defrost every 8 hours. when the cycle slows or quits the freezer will freeze over the evaporator coil and no air flow = no cold air...

Hi, With the information you supplied I’m going to assume there is an ice build up at the rear of the freezer. Your problem is going to be with your defrost system. I will also assume you have the ability to repair this yourself.
This is going to be one of three problems with your refrigerator, 1st thing to do is remove shelf’s and panel in the back of the Freezer. You may see ice build up on the evaporator, don't worry get a hair dryer and melt the ice.
Next locate the wires for the defrost heater and using a multi-meter/ohms meter test the heater for continuity (it should read infinite) if the defrost heater is bad replace it.
This is what a typical defrost heater looks like:
　
If the heater is good test the defrost thermostat. This should normally be done when the evaporator is still covered with ice since it will only activate at 40f - 50f depending on the thermostat. When tested with the ohms meter at below 40f it will read infinite. It is normally clipped to the upper right of the evaporator and look something like this:
The next possible problem could be the defrost timer. If you have tested the heater and thermostat and they have tested good next find the defrost timer, If your refrigerator has a mechanical one it will either be located inside the control panel in the fridge or behind the panel below the doors. Once you have located it advance the dial until you hear a click. This will initiate the defrost cycle. If your heater begins to get hot this will tell you that your timer has stalled and needs to be replaced. A typical mechanical timer looks like this:
If your refrigerator has a digital defrost timer you should locate the tech sheet. Normally you can find this behind the panel under the doors. It will tell you how to initiate a manual defrost cycle. As before if the heater gets hot you will have to replace the mother board normally located behind a panel at the rear of your refrigerator.
If your fridge is warm and there is no build up of frost/ice on the back panel inside the freezer then you problem is most likely going to be the evaporator fan, have you heard the fan running in the past few hours? if you are not sure pull the panel out to where you can see fan and watch it over the space of an hour to see if it turns. If you don’t see it turning replace the motor. This is what a typical evaporator fan looks like:
Hope this helps. If you have any other questions please feel free to comment again. If you decide to get a repair guy in should not cost you any more then $120 - $200 depending on make/model/problem Good luck & thanks for using Fixya! Mike

I believe part number W10135899 Defrost Control Board is defective. The board is located inside the fresh food section and behind the control panel. Near the temperature controls. Look at the rear wall of the freezer. If a layer of ice is forming on the rear wall of your freezer then it also is forming behind the rear panel of the freezer and restricting air flow. The Defrost Control Board is the most likely reason then there are 2 more things to have a look at. That is the defrost heater and the defrost thermostat. Would not be a bad time to manually defrost your freezer so you can bring temperatures down and replace the part. Unplug refrigerator, remove the rear panel inside back of freezer and defrost the evaporator coils with a hair dryer Or you can leave a bucket of hat water setting inside the freezer compartment with door shut for a while. Let me know what you find, again most like problem is the Defrost Control Board, Thanks, Sea Breeze

If your compressor is running and the back wall of the freezer, I would think you have a defrost problem. Because you did not see the model number I will only assume hat the defrost timer or Adaptive Defrost Control is most likely the problem. Look at the bottom of the fresh food section door and behind the door seal for the model number. If your model has a mother board then I would believe the defrost heater and defrost thermostat. Really, of all these thing I mentioned just one will cause it to miss the defrost cycle and build up ice inside the back rear panel of the freezer. If you see frost on the rear wall of the freezer unplug and remove the panel and defrost the evaporator coils with a hair dryer to be able to see your defrost heater and defrost thermostat. Let me know what you find, Thanks, Sea Breeze

How to check everything
http://www.acmehowto.com/howto/appliance/refrigerator/refrigerator.php

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

check defrost timer, defrost heater, defrost thermostat. Inmost 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 clicksand everything shuts down. The heater should now come on. If it does, replacethe timer. If it doesn't, check the heater and defrost thermostat. Turn thetimer again till everything starts back up to end the defrost cycle.

It may just be a defrost timer. Search online for information. There is plenty to be had. Check with the website of GE for a parts breakdown or your manual if you still have it for the location of the defrost timer. You can turn it manually so it goes into defrost. Does the unit seem to be running all the time and never shuts off? If so that timer could be stuck in the cool mode and the evaporator is freezing up solid so air wont flow over it to properly cool. I've had two refrigerators I've had to repair that had defrost timer problems. One stuck in the defrost cycle and wouldn't turn on to cool, the other did what you are describing. It stuck in the cool cycle and wouldn't defrost you may need to manually bypass the cooling cycle several times to allow it to completely defrost. Usually it cycles in cool from 6,8 or ten hours and only stays in defrost for over twenty minutes. That should defrost it and allow it to start cooling again. If you notice that frost has disappeared inside on the wall replace the timer.

It is probably the defrost thermostat located on upper condenser coil to the left of the fan in the freezer compartment. If not, it could be the defrost timer located near the thermostat in the refrigerator under the plastic dome where the light is. If the defost thermostat or defrost timer is not cycling the defroster heater element on and off correctly... an ice dam forms clogging the drain tube which freezes and blocks water (from the the defroster) to draining down and into the evaporator pan located on top of the compressor in the rear of the unit near the floor.