Freezer vents are building up ice.

Check your defrost timer. It may be bad.

when it stops cooling, you will see some ice build up in the freezer. Letting it sit unplugged melts the ice and you will see some water under the fridge. Connect power and it works. Cause: don't overload the fridge and the freezer. Make sure the doors close snugly. Clean all lint build ups by vacuuming under and behind the fridge after switching off power.

Could be that the freezer is too full with foodstuff and there is no air circulation, therefor, some places in the freezer build ice. The defroster is working and melting the ice that drips to the bottom bins.
I suggest you remove everything from the freezer. unplug the frigde. Let all ice build ups melt. Remove ice from the foodstuff and put back in. Make sure that vents in the freezer and fridge are not blocked.

Bonjour,
That's not a potentiometer you turned it's the defrost timer gear knob. What you were doing is aborting the defrost cycle and allowing frost or ice to build up on the freezer coils. It built up enough to clog the airflow and the temperature in the freezer started going up. The compressor seems to be operating normally.
Follow along through a defrost cycle
To start defrost the defrost timer stops the compressor and all fans. Next it turns on the defrost heater. This melts the ice/frost off the freezer coils. The water drips down the drain line to the drain pan under the unit. If the defrost heater raises the temperature too high the defrost termination thermostat turns the heaters off. When the defrost timer times out it turns off the heaters and turns the compressor and fans back on. If the drain line clogs with food the water does not drain out and when the compressor starts again the water freezes. If this keeps happening the ice gets higher and bigger until it clogs the coils and the freezer does not get cold. If the defrost termination thermostat turns off the defrost heaters too soon all the frost is not melted from the coils. And the coils soon clog and the freezer gets too warm. If the defrost heater is bad no frost gets melted off the coils and the airflow quickly gets clogged. No defrost usually means either a bad defrost timer, a clogged drain line, a bad defrost termination thermostat or bad defrost heater. You can take a chance and replace the defrost timer. If that's the only problem your back in business. OR
If the drain line is not stopped up you can try this.
Remove all food from freezer and refrigerator, open the doors and unplug the cord. Wait 24 hours for all the frost/ice to melt. Keep the doors wide open and the cord unplugged the whole time. If the drain pan fills with water that's a good sign that the drain line is not clogged. Empty the drain pan often to keep water off the floor. After 24 hours the drain line should have stopped dripping water. If it's still dripping wait until it stops. Plug the cord back in, close the doors and wait for 1/2 cup of water to turn to ice in the freezer. Then you can put the food back in. The problem will return if the unit is not defrosting. Changing a defrost timer is not too hard. Unplug the cord. Locate the defrost timer. Take out the mounting screws and remove the part. Unplug the wires, plug them into the new part and remount it. Don't forget the ground wire if it has one.
Plug the cord back in and see what happens. If you did not defrost the unit turn that timer knob very very very slowly until you hear the compressor stop. Then wait to see if the drain line is dripping water into the drain pan. If it is your in business. If not either the drain line is clogged, the defrost heater is burned out or the defrost termination thermostat is bad and has the defrost heater shut off.
OR Or you can call a service technician.

Your drain is plugged. Basically the freezer goes into defrost and melts frost off the condenser coils. A big piece most likely fell off and freezer came out of defrost before it coulld melt and drain out completely. To fix you have 2 options. Have towels
#1- move contents of fridge and freezer to a backup fridge. Leave unpluged with doors slightly opened for 24 to 48 hrs. Use towels to cleanup any water. Plug back in wait 2 hrs to make sure temp gets back down before putting contents back in fridge.
#2- Remove contents from fridge and put in ice chest. Have towels ready. Remove ice maker ( if there is one) usually two screws on top hard to see and one on bottom. Disconnect the quick connect for the ice maker. Remove screw on back wall. Be careful when removing air vent on back wall. Its plastic and can break. Remove back panel. Look on the silver plate under coils and you will see ice and where the drain is. Remove ice than pour hot hot water down drain until it flows freely into drain pan under fridge by compressor. It may look like there is not ice make sure othyerwise you will be doing this all over again in a few days. Once water flows freely put everything back together wait about 2 hrs for freezer temp to get cold enough and than you can put contents back in freezer. If you have any question or need help please feel free to comment me back.

A couple of things can cause this problem. One is that your defrost temp sensor is ot functioning correctly and terminating the defrost cycle early allowing ice build up to occur over time. The other thing could be that you have a torrn or loose door seal on either your freezer or your food section door. The thrird possibility is that you deftost timer is intermittent and only working part of the time or is clocking forward at a very slow rate. You can unplug the unit again and place a fan blowing into the freezer section for about 2 hours but we both know this is only a temporary situation and that you should have your unit serviced. I would call for that service either before you defrost it or 2 weeks after you defrost it.

I removed the freezer drawers removed back panel inside the freezer,and discovered that ice had built up around the vent which cools the fridge compartment once I melted this using a hair dryer put it back together and the fridge compartment works fine.

Could be the defrost element. If it does not work and melt the ice off of the evaporator, icing will continue and serve as an insulator. Freezer and refrigerator temps will suffer.
If you unplug the unit and let it defrost for a day and plug back in it will work fine till it freezes up again.

Hi,advance thermostat setting, to get colder , it's possible you got defrost problem, is there excessive ice building inside back of freezer? to determine if you have a defrost problem, unplug ref. for about an hour,let it defrost, let all ice melt away, it's better to remove your produce, keep doors open to speed up defrosting, after defrosting and cleaning plug back your ref, and let it work for another hour, and check result, if it's o/k, put back your produce, let me know, during hot summer months, regular use (opening) of ref, could cause excessive ice build-up evap. if after defrosting and cleaning ref. work good for 3 to 4 days, but start doing the same thing, let me know, it means you got a defrost problem. also check your thermostat, but first defrost and clean it, that could just be your problem. good luck.

Make sure your fan is working ,its located behind the freezers back wall. If it is working the vent from the freezer down to the refrigerator may be blocked (usually with ice).With out a fan you have no circulation but your freezer may look likes its working,it may last 3 days.Also if you can move everything out unplug it turn it off w/ doors open untill all traces of ice are gone this will free up any clogged tubes. Good luck.
Len West