Defrost issue Seems every once in a while the bottom freezer ices up and the top refrig gets warm. If I manually twist the little red knob under the refrig (defrost timer) until it turns off it seems to work great defrosting the freezer. I do it like 2-3 times and it fixes the issue. Kenmore 596.71103101 about 5years old. Gasket seems ok, maybe it needs to be cleaned? Also, i just vacuumed a ton of dust off the coil/radiator looking thing underneath of the refrig from the front. since this keeps happening time to time, what is the likely cause? timer, thermostat, heater? thanks!

If it's frost free check that the fan is running in the freezer section.
If ice is causing it to stop then it your defrost control that is causing the problem

this fan needs to run when the compressor runs,check fan blade for being jammed by ice if you have this much ice on back wall as ice will stall motor,if no fan there will be no cool air to refrige compartment also the defrost drain tray will fill with water then freeze over which in turn floods the freezer floor and refrige compartments cause it cannot drain to the pan in the bottom

the freezer is not going into the defrost cycle properly. first completely defrost the freezer compartment. to do this you first remove all the food from the freezer compartment then unplug the refrigerator from the wall. next put a large pan of very warm water in to the freezer and close the door. the heat from the hot water should melt the ice off the freezer coils. if the drain is working the water should go down the little drain into the catch pan in the bottom of the unit( way down underneath next to the floor) if it doesn't drain down use towels to soak up the water then find the little hose and drain that go to the bottom and clean it out. if the drain was blocked that could cause the ice build up. If the drain is not blocked then the defrost timer or the defrost coil is not working. the defrost timer is a small unit usually located behind the kick plate at the bottom of the fridge or sometimes at the back behind the paper shroud. this is the manual advance knob and should allow you turn the knob until the defrost position is reached. you should hear a little click as it reaches the defrost position. make a mark on the timer knob with a magic marker and then plug the refrigerator back in. over the next 4 hours you should see the knob turn (like a really slow moving clock). after you plug the refrigerator back in watch for ice build up on the coils. If it starts to build up again you will need to figure out if it is the defrost coil or the defrost timer that is not working. the manual defrost technique will keep the unit in service but is a total pain. eventually you will need to replace the defrost coil or once in a while it is the defrost timer that doesn't work. this is not easy even for the repair man but it can be done. first locate the defrost coil(a long thick wire looking thing) and check for continuity. if you don't have a multi meter and a basic understanding of the repair technique you should get professional help. to keep the refrigerator running and keep the ice off the coils you will need to repeat the defrost procedure from time to time. this is not that easy to do but will keep your refrigerator running.

The evaporator coil behind the cover on the back wall inside the freezer will ice up under normal conditions. Every 8 to 10 hours for around 20 minutes the defrost timer (or in most newer models the electronic adaptive defrost control) will turn the defrost heater on to melt the built up ice. There is a defrost thermostat which prevents the heater from overheating the freezer by breaking the heater circuit when the temp reaches close to 32 degrees F. The entire cooling system shuts off during the defrost cycle and starts back when the timer advances through the cycle.

If this ice is not melted it will continue to build up until the air can't flow over the coil to circulate the cold air through the freezer and into the fridge. The temperature change in the fridge is usually noticed first followed by the freezer.

If the defrost thermostat is bad, it can prevent the heater from coming on OR it won't turn the heater off when it gets too warm. It is clamped to the evaporator coil at the top to sense the temp. If it appears to be misshapen it is bad.
With an ohm meter it should show continuity when cold and none when warm.
You can also bypass(disconnect the two wires plugged into it and twist them together) the thermostat to see if the heater comes on then. If it does then you know the thermostat is bad and needs replaced.

Pull the refrig out and remove the 8 " x 10 " panel . Behind this panel , is the main control board . Unplug the refrig . Remove the BLUE plug from the board , with 3 larger wires going to it . Looking at the blue plug , the sequence will be wire1,wire2,space,wire3 . Get a short piece of insulated wire , and strip about 1/4 inch from each end . Insert 1 end into wire2 , and the other into wire3 . Plug the refrig back in . After about 3 min , look in the freezer , at the bottom , behind the crisper , look for a red glow . If no red glow , unplug the refrig , and reassemble the plug and cover . This no glow , indicates a shorted defrost heater WR51X10101 . It is also advisable to replace the defrost thermostat ( pt. number WR50X10068 ) when replacing the heater . To access these parts , you will have to remove the inside rear wall of the freezer . The heater , is at the bottom of the coils , held on with 2 screws , and the thermostat , is the 1 " cylinder , with a blue and pink wire going to it , clipped on the top left of the coils .
If you do get a red glow , then the # 4 thermistor is bad . This tells the main control board , the temp of the coils , if they need defrosted , when they are thru defrosting . This thermistor is the 1 " long , torpedo looking piece , clipped on the top left of the coils , with 2 white wires going to it . Part number WR55X10025 . It would be advisable to also replace the # 5 thermistor , located at the bottom of the freezer , slightly in front of the drain , also with 2 white wires going to it , slid into a housing . This thermistor , is the freezer thermistor , which tells the control board , the freezer temp and when to cycle off due to selected temperature .

Most likely evaporator coils are iced near solid...few hours unplugged would have helped just a little...needs major defrosting though.
The automatic defrost cycle will never fix it when it gets this bad...if it's still working yet.

I have one of these and have had to use heat gun/ hair dryer more than once to defrost it.

Probably the cause...which will need fixed or it will do it again sooner or latter...is the melted frost/ice goes down a little drain tube and dumps into tray to evaporate above coils...this tube gets plugged first with dust and then when melted frost drains and stands in tube the tube get plugged with frozen water.

You see it is important to unplug or fridge will self destruct.

This can have several causes. 1) If the fan in the freezer is working (it will usually turn off when you open the door), then it is usually a defroster issue. If the fan is dead, then it's the fan.
Assuming it's the defroster, and the refrig is old enough, or inexpensive enough to not have any computers or fancy displays, the it is usually the defrost timer that is bad. Depending on the model, the timer is usually underneath the front kick panel, or more often near where the knobs are that control the temperature. Try finding the defrost timer - it may be under a removable plastic panel where the knobs are or where the light bulb is, and if you do, there is usually a knob on it that you can turn with a short, wide screwdriver or coin. Turn it until the refrig turns off and this will start the defrost cycle. It may take a while to melt the ice. The ice is under the bottom or back panel in the freezer. You can remove the panel with a couple screws and melt the ice with a hair dryer also. Assuming this was the problem - that the timer is no longer working, you will have to turn the timer again to start the refrig back up, unless moving it got it running again. By defrosting it manually, you have bought yourself a couple days before it ices up again, so go and buy a new timer. Occasionally, the problem could also be that the heater coil is shot, or the wire to it has rusted off, or a small temperature sensor attached near the coil is bad, but it is usually either the fan or the timer. By the way, there's usually a wiring diagram on a folded piece of paper hidden somewhere behind the kick panel. Good luck.

hows the freezer?? is only the refrig warm and freezer still frezzing?? if so id open the freezer door and listen for a fan motor, it should be spinning to circulate air to the top sect(refrig). if not on sounds like a bad fan.. if the fan is on but the rear panle is completly iced over, sounds like a defrost issue

change the adaptive defrost board located in the upper right corner of refrig under the panel. remove panel by pulling on panel towards you from the finger holes in the rear. remove two 1/4 inch screws and two phillips screws. defrost manually with hair dryer behind panel in freezer.

Same problem with Frigidaire Gallery model#GLRT182SAW5 (dated 2002 on back of case)

Vents were blocked with ice. Vents (from top compartment to lower) located behind light. You can check by poking a chopstick up the (2) holes; be careful not to hit fan blades.

Solution:

- took freezer coil cover off in back; checked that defrost heater element was working (marked and rotated the timer in the hole next to light); checked that fan working. Found ice in the vents and defrost drip area. Got it out with hair dryer.

- cleaned compressor coils in back (check fan is rotating; also tweaked some of the compressor tubing bends to make them more smooth - read somewhere about a manufacturing defect ...); blew out drip tube from defroster while down there.

- Set the freezer control to WARM and the refrig control to COLD (THIS SHOULD IMPROVE AIR FLOW FROM TOP TO BOTTOM).

- Put thermometers in top and bottom. Checked that refrigerator cycles (not running continuously). Checked that cold air is coming down from (2) vents behind light.

OK: so far, so good. Lower compartment is 40 or under. Top is under 18.

CONCLUSION: Suspect marginal design. Had problems with another similar model where defroster ice doesn't drain correctly, pools and refreezes. Leading to blocked vents as well as blocked defroster drain and similar problem including dripping water from top to bottom and warm bottom.

MAYBE KEEPING THE FREEZER CONTROL AT WARM GETS AROUND THE PROBLEM?? ANYWAY, ITS WORKING FOR ME FOR NOW !!