How To Test Your Defrost Thermostat & How They Work 

Thank you for the video. I ordered a timer and a thermostat. the T Stat was busted open like the bad one you showed. Great video. This will be my second time replacing these 2 pieces. the first time was over 10 years ago and that time the fridge was about 7 years old. I'm hoping it last another 10 after this. $45 worth of parts saved me $1000.

You make the best videos. No frills, complete information & will sell me the parts.. Awesome!! Thank you.

Very very well explained, this is the best defrost thermostat video ever.thanks

Good video. Whenever one of our fridges starts acting up around 8-12 years (icing/warm refrigerator usually) I replace all the main defrost components and put the unit into a rental. It's usually around $180 to do the timer, heating element, thermostat, cold control and maybe a cracked plastic door bin or two. Can't believe the cost of new fridges - used to buy basic rental property fridges for $249 vs. $1000 today. Too much printing of fake money.

Thank you kindly for your SPOT ON video regarding the defrost thermostat. Especially the decoding of the open and close temperatures. As a hint, ICE CUBES taken out of the freezer are typically about 0F. So if you have a second working freezer compartment, you can place the thermostat in the ice tray for 10 minutes, and then remove with this ice WITHOUT WATER to reduce the defrost thermostat temperature. To take the temperature, some meat thermometers do get down to 0f. Fortunately my digital volt-ohm meter was purchased with foresight and comes with a temperature probe. God Bless You and God Bless America.

Thank you Ryan, thank you! My thermostat is EXACTLY the same as the one you showed, it was even blown up the same!

I have been an appliance service tech for 7 years now Still like watching these videos lol

Great video. Thank a lot for explaining so clearly.

excellent video. simple and straight to the point

I've replaced many defrost thermostats that have had a blown top, but never really knew how to test them. Thanks Martin Larsen

Great video! Very helpful in explaining the part #'s on the defrost thermostat! I have a defrost thermostat L47-22F 240386402 on an electrolux bottom freezer fridge (Model #EW28BS71IS9) and the top part is popped off partially like you show in the video. Again, that was very helpful explanation on why that happened! The heater element tests fine and hopefully the control board will be okay because it's hard to find details on this fridge! Thanks again for such a helpful video. :)

Very informative, thanks for giving us shade tree mechanics the info we need to make an educated diagnosis. Your vids are always very helpful

Thanks for the bulge explanation. Now I know what to replace!!!

what is the common problem of haire refrigerator not working on the motor compressor but the led light only flashing model 663w thanks

Excellent. Thank you.

Hi can i ask a question about my mini samsung ref. I left my ref for 3months with doors open slightly when i came back and turn it on the compressor is just humming but no fan and not freezing, what may be the problem? Thanks

Great video, i will be ordering my part tomorrow!

would a faulty thermol fuse in the freezer compartment affect the function of refrigerator side is there any link between the two. on the samsung RS21 JGRS model. i have had a brand new kit put on. still having defrost problem on fridge side. rechecked all the components for faults, they all good. Have been told it could be the pcb board not letting the heaters stay on long enough. is there anyway of checking my pcb board myself.

Great video 😊 Thanks 😍

hello, my mini fridge turns on but when it reaches the thermostat setting temp.... it won't turn back on. can this be a thermostat issue or something else?

Hi, I have a Ge double door, compressor works, Freezer fan works, the cooling fan in the back works the freezer is cool, and the fredge side is bearley cool. What should I do ? thanks

Ryan, my MAN! great video

Thanks! This was exactly what was wrong with my Kenmore.

Very clear. Thanks.

You saved me money! , thank you very much

great video

Very good 👍 job

Great info,thanks Next level!!

good lesson...tq for sharing..

good explanation!

Hello,can you help me ?I bought used viking VCFF036SS fridge for repair. I opened the back panel and I saw the smoke pipe left side of compressor have small hole and the right side of the compressor the tiny pipe it's broken, when I contacted the fridge the fan turn on ,the light turn on and that it. I think the fridge have another problem... What I have to do? Or it's better to sale for parts etc.. What I have to do? Thank you!

@Parts Dr Hi, first of all wish u a merry christmas and tks for this video. 2nd is the defrost thermostat stops the compressor and the fan on defrost cycle only or also when the ice is reachs its limit in the freezer too? My fridge is whirlpool model #3VET16GKBW00. I wld really appreciate ur answer 🙏

Hello from Greece I have a question. I have indesit ban 33 ND p and after a sort power down the 2 leds start blikin after few hours and after this no work properly I open the back of freezer and I see a lot ice if I check what you say maybe I find the problem? The fun works but no cool like the past. I try what you suggest and I hope to solve the problem.

Very good information bro

I wish I had seen this video a few hours ago. I just replaced my defrost thermostat after using the place-in-ice-water method, and I think it may not have been necessary. My timeline: my fridge was not getting cold enough. I realized it the day before going on a trip. I vacuumed the (very dusty) coils at the bottom, and the next morning the fridge seemed colder, but I thought I should order parts just in case. I ordered a heater and a thermostat. The fridge seemed to be operating normally when I returned from my trip, but I had the parts, so I thought I'd go ahead and dismantle the freezer and test the existing parts. My intention was to return both parts if the old ones passed the tests. I opened up the back of the freezer and there was no ice on the fins. I thought, great, the existing heater works! I cut out the thermostat, placed it in ice water, and didn't get continuity. So I decided to go ahead and put in the new thermostat. Because I'm not experienced with using a multimeter, I thought I'd test the new thermostat to see how the test should work. To my surprise, the new thermostat also failed the test! Stumped, I thought I might as well install the new thermostat, since I had opened the package and couldn't return it. My fridge is now gradually cooling off. Now I have seen your video, and can attest to your statement that the place-in-ice-water method of testing is not adequate. I'm going to let the site from which I bought my parts know about my experience. I cleaned the fridge thoroughly, so at least now I have a nice clean fridge to show for my efforts.

The thermostat and the heating element are good however the cooling problem persists. What else could it be ? Thanks

My freezer has black dirt in it and after that my fridge stopped working well after some weeks. Is black dirt that suddenly appeared a symptom of a bad defrost thermostat like it blew out?

nice information

Hi Thanks for being here :). I just put in a defrost heater. It read 26 ohms before I put it in. When it came on the the defrost cycle. I could see through the vents it was glowing red. Then a few minutes later it turned off. Should I expect to see a "Glow". Thank you

Thank You!

Thanks for your videos AND advice!

Great video. I changed my thermostat refrigeraror, but the refrigerator is still working constantly. The refrigerator it's very clean below. So what could be the problem?

thx...good job!

Hello, Our fridge is a Whirlpool Gold side by side and the fridge starts clicking and seems to go defrost mode a lot lately. It still cools ok in both parts of the fridge. It shows digital instead of 2 to 15 and fridge side 39 to 46 and then it snaps out of it and is back to 2 and 39. Can this be the defrost sensor? I ordered a new condensor motor/fan but suspect since the fan seems to run when its not in defrost mode its not the broke part. I notice when I press the quick cool button the thermostat numbers switches to freezer -6 and 34 fridge and it truly cooling like shown. Thank you for any advise.

Sir very nice video Hi how are you..sir my refrigerator not automatic off I did change timer and biometal..but not automatic off..what problem sir guide me I'm very upset about refrigerator....

Great video thanks

I am looking to get some type of training in small appliance repair. I am a certified HVAC Tech but I want to change careers. Any suggestion?

Wow !!! Amazing video , you guys rock !!!

Hi please I need help a nonfroze refrigerator am working on product Hisense doorbell door freezer and fridge the up side is the freezer is working but fridge is not

Thank you super helpful i have one question what if the thermostat is between the 55 and -15 should there be continuity or not? Thank you for any help

Thanks.... good video 👍💪

Very good 👍

I have been sweating over my used "patio fridge" (Amana) for a couple of weekends now. The evaporator fan did not work with the door open, but when I pulled it out it tested fine. Then I started looking at the defrost thermostat, and was just fixing to dangle it in a cup of ice water. Noticed that it was bulged like in your video, so I will order one and see if that was the problem. My other plan was to buy a different fridge from Craigslist.

Muchas gracias

I have open the component up in the freezer n what see is evepartor full of ice

Great video. I replaced both the defrost timer and defroster thermostat on my Hotpoint freezer refrigerator with the freezer located on top. Originally the refrigerator is not cooling. Now the refrigerator and freezer are working fine but I constantly hear the fan on and the back of the refrigerated which means they're refrigerated is not turning off. Any suggestions please help

great video!!! freezing it instead of cold water!!!

verry good info.

Good info.

I have a Sears Kenmore Fridge with Freezer on top model# 253.6480240C. Found that food was partially defrosted in freezer. The freezer temp is only 32F and the fridge temp is only 48F. I used a screwdriver to manually advance the defrost timer and that did turn on/off the the sound of what I believe to be the compressor as well as the freezer fan. Turning the fridge temperature control knob from lowest setting (left) to highest setting (right) also turns on and off the same sound. I clamped my multimeter on to the red wire near the compressor and it read ~ 1.6 amps when I believe the compressor is running. The freezer fan is definitely rotating as cold air is being pushed out of the freezer vents. I removed the freezer evaporator cover and confirmed the fan is rotating. There was a 3/4 x 2" chunk of ice on the tube (that does *not* have the thermostat attached to it) right near the fins of the evaporator, otherwise, no real icing in the freezer. The defrost heater element has continuity. I am suspecting the defrost thermostat. I don't want to cut the wires just to test unless I'm on the right track. Is this the next likely culpret that should be tested? Any advice?

Good video!!

Wow the info I was looking for! I know this isn't a forum but just to get a clear understanding. My thermostat is rated at 14.4 - 22.2C. So no continuity at room temp (approx 70F) then threw the thermostat in the freezer which was reading at at 0C. Checked and I had continuity, this means I have a bad thermostat?

GE IC360NMARH Bottom freezer. The original Evap Thermodisc L65 - 20F while its replacement WR50X10030 L140-30F. Does not seem that these sames parts could operate the same in the freezer and be a suitable replacement. Can i expect the new part to operate satisfactorily? Glad i found your site on RU-vid.

Awesome video.. I understand the 55 degrees or higher there is no continuity. This is the case where the heater element has been on for several minutes and the thermostat opens to cut off the heater. I also understand the low end number which is the typical case where the defrost timer kicks in and the thermostat is like way down near zero or better degrees and the circuit is closed so the heater is safe to turn on. What I don't understand is what's going on with continuity in the middle range between 20 and 55 degrees? I am assuming the thermostat is closed allowing the heater to work until 55 degrees is reached. So why the 20 degree figure? Why not just have one figure - open above 55 and closed below 55 degrees?? Thanks for explaining. Great video once again

great video and very educational. My kenmore side by side fridge is in the garage and the evaporator fan keeps running. I've done the diagnostic checks to include forcing the heater to come on. The whole time I was in diagnostic mode, the evaporator fan was on. It seems like the thermostat is the problem but I can't be sure until I open it up and inspect the thermostat. What else do you think might be the problem?

My refrigerator is warm ( side by side fridge/freezer) my freezer isn't freezing food anymore what could that be?

Very good

Awesome!

Thanks for the explanation. there are two Thermostat in my fridge (Amanna)' one is L55-35F and L90-45F. why two?

Bimetal sometimes pass the continuity test , but the contacts dont hold when the heater comes on, so the continuity test is not 100% reliable, I learn with experience whenever I replace the timer or heater I also replace the bi metal tio avoid recalls

Good video I like it

I wanted to ask you my closed is L60-32= 28 degrees for a closed circuit. Wr50x10090 is only putting out 2.7 of resistance when I check. I noticed yours was like 6.5. Is 2.2-2.7 at like 18degree ok? I also checked the heater element it was like 40-50 ohms. I have the G.E. GBSC0HCXCRBB

thanks

Thanku sir

Hi, In May of this year. I had a "DEF" flashing off my GE Profile door monitor. I got a thermostat and a thermostat timer from Appliance Part Co. in Tempe, AZ. Installed them both and after a day "Def" flashing came back and ever since I just unplug and plug it back on. Today I decided to pull the back panel again and manually turn the defrost on thru the timer. I heater came on. I dbl checked the thermostat and to my surprise the the numbers on the replacement part is L140-30F. That says an opening of 140 and a closing of 110 degrees F. Is that why I am having a problem. I am going back tomorrow to that parts store. I appreciate your feed back. Thank you.

Our Samsung French Door Refrigerator bottom freezer bimetal defrost thermostat doesn't seem to have any "L" numbers, only 100 10 and 60 / 40. What do those numbers mean? Also, at room temperature it had a continuous beep when we put it on the ohm meter. We're trying to figure out why the bottom freezer fluctuates in temperature between 0 degrees and even up to 30 degrees. Ice cream is soft and ice is slippery.

If the descriptions says L55-35F what is happening between 55 and 20 ? is it partly opened/closed? What does that mean?

Thank you for the excellent video.. as usual. My thermostat has 100% continuity..doesn't that mean that it's in constant defrost mode? However the evaporator still ices up while my heater, sensor and fan are fine thanks to your excellent testing videos. Is it possible that although the defroster shows constant continuity, that it's just totally bad and the control board is not getting any signal to turn on the heater(even tho as mentioned) the heater should be on constantly....thank u in advance for any reply...

my multimeter in the continuity setting showed 001 after the thermostat was in the freezer for a few minutes. The same reading as when I touch the probes together. Is this saying that the thermostat is good?

I have one I checked with meter set to sound. Checked good. But when I set meter to Auto, I get a high reading of resistance. Does the bi-metal in the stat ever lose or gain resistance? This fridge was freezing over. Df element checks good. I have yet to check the timer. If I turn the timer to defrost and the heater comes on and goes off in the time it is supposed to, can I trust the stat is wirking properly, or are they like dryer thermostats that might check okay when ohmed but still be faulty?

Ha he sounds like that dude on Better Call Saul. The one who the the flamed our H2 with spinners.

Awesome and informative video! Mine reads L140-30F so using your example it opens at 140F degrees and closes at 110F degrees? Does this seem right? It seems very hot compared to the example you gave. Please help!

Hello dear sir l serviced freezer its temprature reading is -18 to -26 .its full cover with ice so i seviced what it is not show proper temprature -18 to -26.it show only -16. what is fault in this machine.

I was having the symptoms of a broken thermostat - icy coils and warm refrigerator. I noticed the defrost thermostat was popped up like in the video, but it does have continuity when cold. I went ahead and replaced it. Hoping it solves the problem, but I’m not sure if it will.

CORRECT Info, GREAT video! Question: I just replaced a defrost thermostat (it lasted one year) - it was a 48 - 18 = 30; the new one I put in was 48 - 30 = 18. Any idea if this new thermostat will work, or should I go ahead and order one like I just removed? My unit is an old Top Freezer Roper RT18BKXKQ03. PS: I can't find the specific specs for what the thermostat specs should actually be. THANKS!

Does this and the hearer element run 120v AC or is it converted to DC? Glass heater element was burned up, but after 30min im not sure its workinf as the tube isnt warm.

Nice video clip. So - after watching this video - this device is electrically connected in series with the heating element right? So if the temperature gets above a certain temperature ----- then the device becomes an open circuit ------ which prevents any more heating until the next defrost cycle occurs, right?

Quick question. How would you interpret a bimetal/thermodisc labeled F42-32F? Does it work differently as in closed when above 42 degrees and stays closed then cuts open at 10 degrees? This part is wired in series with a cold control thermostat, not a defrost heater.

My multimeter doesn't have a "continuity setting" (with the symbols shown on yours). It does have all the other stuff.What exactly should I set it to? I thought continuity was ohms? Tested the heater and it was 29.4 ohms. So I'm thinking it's the thermostat even though it looks fine. I guess I'll have to turn it back on without the heater and thermostat and leave it in the freezer to get it cold. Mine has no numbers on it though to say how cold or warm it needs to be.

Now I do not know what is wrong with the refrigerator. After watching several videos. Your was the first one I have found that explained to take the first number and subtract the second to find the where it kicks off and on. I was screwing around with ice water and all I did was make a mess. So I put the thermostats in a freezer and found the one I had was good. I bought 3 new ones thinking the first new one was bad. Now I have 4 good ones and still have No idea as to why the side by side is freezing up. I know the heater works, The refrigerator I have has the electronic box inside, not the defrost type you can turn the screw to get it to kick on. I found that if you hit the light switch 5 or 6 time quickly it will go into defrost mode, that is how I got burned. I did not feel any heat off of it, so I got brave/stupid and touched it. A few moments later I could hear water steaming off of it.

i have watched a bunch of your videos while i diagnose my fridge during covid days. but i want to buy some parts from you but you don't ship to canada. thanks for your videos. very helpful.

The defrost thermostat for my kenmore fridge has this sequence of characters on it. L8.9-16.7C. Converting to Fahrenheit it comes to L48.02-62.06F. This seems backwards in that the first number is lower than the second number and the close temperature calculates to -14.04F. What is wrong here?

I have a kelvinator chest frezzer comp is running but not frezzeing what wrong thx you

Is there any problem with the wires? The original has orange and brown same size length, the new one yellow short and orange large?

if the thermostat is New and never been tested. when testing it at room temp should there be continuity or should it be a open circuit

my freezer works and I removed the cover to expose the coils. They had some frost but not much. I defrosted them anyway. The frig is still not cooling. what next?

Hi, what is the diagnosis if: Defrost heater, defrost thermostat and timer also work but the fresh food section does not get cold air due to ice build up, not on the evaporator (freezer section), but at around the freezer openings? Thank you

Is defrost thermostat interchangeable, C to F or vice versa? For example, my original defrost thermostat uses F, if I replace with new one with C, will it still work? Or I have the same version F? I have replaced start relay, capacitor, defrost thermostat and defrost sensor Added new freon. My Kenmore bottom freezer refrigerator still does not work. The temperature is 57 F for the fridge, 27F for the freezer after 1 1/2 days.

I use dust off held upside down to close them, because most time you go into a house with only one working fridge/freezer.

what will happen if not the right specs is installed...like my bad thermostat is hotpoint and i plan to replace it with my spare thermostat from frigedaire?