How To Test Your Defrost Thermostat & How They Work

This video shows the proper way to test your defrost thermostat. There is a lot of misinformation on testing the defrost thermostat. Most defrost thermostats CANNOT be tested in a glass of ice water because they have a closing temperature that is colder than 34°F.
If you find that you have a bad defrost thermostat you can shop for a new one on our online store by searching with your refrigerators model number, or entering the part number off of the old defrost thermostat here: partsdr.com/app... We sell new OEM appliance parts for Whirlpool, Maytag, Kenmore, Amana, Estate, Roper, Frigidaire, Electrolux, Tappan, Westinghouse, Kitchen Aid, Jenn Air, Bosch, LG, Samsung, and more.
If your refrigerator is not going through the automatic defrost cycle then you will need to test the defrost thermostat on your refrigerator. When the refrigerator stops going through the automatic defrost cycle the refrigerator will not cool properly because the frost will block the air flow on the evaporator coil and cause the cold air to stop circulating. The defrost thermostat is usually located behind the back panel in the freezer section of the refrigerator, and it is usually clipped onto the evaporator coil.
Get Social With us!
/ partsdr
/ parts_dr
Check out our appliance repair forum: forum.partsdr.com/
Check out our blog: partsdr.com/blog/
Subscribe to our KZbin channel: www.youtube.com...
If you found this video helpful please click the thumbs up button and leave us a comment below.
#PartsDr #MakeAppliancesGreatAgain #Refrigerator

[@zgwforum]

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.

[@PartsDr]

🇺🇸

[@madcowusa4277]

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.

[@PartsDr]

Very smart!

[@bdkj3e]

Isn't it amazing how basic of an idea it is yet all our so called "experts" are always shocked when printing more money makes inflation go up lol.

[@ridcully]

One simple trick - adopt the gold standars

[@francom6230]

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

[@condor5635]

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

[@PartsDr]

Great question! It is because the manufacture does not want the thermostat to open and close at the same temperature. What happens in the middle depends on whether the thermostat is in an open or closed state. For instance with the numbers you provided, if the thermostat is at 37F it could be opened or closed. If the thermostat has already down to 20F or colder and it is closed and it has warmed up to 37F then it would be closed because it hasn't warmed up to the 55F to open. If the thermostat has opened by warming up above 55F, then the thermostat cooled down to 37f, it would still be open at 37F because it hasn't reached the closing temperature of 20F.

[@condor5635]

Thanks for the great reply totally explained it well. I had an interesting way of checking my heater defrost element sticking my Fluke temperature probe in a screw hole down near the heater element which allowed me to see the temperature go up to 108° verifying that the heater cycle was working correctly without taking off the entire panel which is a real pain in my GE fridge. Love those Fluke instruments Thank you

[@wyocoyotewyocoyote9007]

@@PartsDr this reply really helped....but still need a bit of clarification. I have 25-47F Bimetal Tstat,connected to my Ohm meter from below freezing warming up it switches from continuity to no continuity right around 25 F (according to my digital temp sensor tool )so from closed to open circuit as temp hits to 25. Then it will stay open if it goes up and past 47F and not close the circuit again until it drops past 47?

[@PartsDr]

​@@wyocoyotewyocoyote9007 Most bimetal defrost thermostats that we have seen open at the higher temp rating and close at the colder temp rating. So if yours worked that way it would open at 47F and close at 25F. These are general rules and each manufacturer can do things differently if they want to. From the results you got it sounds like yours opens at 25F and closes at 47F and should be just fine as long as it works that way consistently.

[@melikey4398]

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

[@PartsDr]

It would depend on the temperature of the thermostat.

[@jacksdad2626]

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

[@PartsDr]

The fans are controlled by the cold control thermostat. First set the temp controls to the middle factory settings. Then wait 24 hours; opening the doors as little as possible. Next, check to make sure the refrigerator and freezer are cooling to the proper temps (37F Fridge section, 0 Freezer section). If you aren't getting those results then the cold control thermostat is most likely bad and needs to be replaced.

[@MrTonyshit80]

good lesson...tq for sharing..

[@PartsDr]

+MrTonyshit80 You're welcome!

[@toddlemmon]

Ryan, my MAN! great video

[@PartsDr]

Thanks!

[@johnhenson757]

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 KZbin.

[@PartsDr]

We can think of a few possible reasons the new and old thermostats would have such different temperature ratings. 1. Someone replaced the thermostat at some point in time with something other than the OEM part. 2. GE made a design change to the part. 3. GE has the wrong part number listed for your model refrigerator. It might be best for you to contact GE directly to see if they can clarify what the correct temperature rating for this part should be on your refrigerator. Our records indicate WR50X10030 should be L140-30F.

[@romiep9557]

@@PartsDrfor L140-30F, what is the closing temp? Thanks

[@PartsDr]

@@romiep9557 It should be 110F. Please reference our other video that goes more in depth on these high limit defrost thermostats here: kzbin.info/www/bejne/n2W2f3idhdSIg7s

[@carlostrejo8699]

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?

[@PartsDr]

What is the model number of the refrigerator?

[@carlostrejo8699]

@@PartsDr 10656573400

[@PartsDr]

@@carlostrejo8699 The fan motor is probably controlled by one of the control boards on your refrigerator. It could run constantly if it isn't cooling cold enough.

[@carlostrejo8699]

@@PartsDr well....that's the peculiar thing, it is cooling. I thought the temp control was set too low thinking it might be trying to reach that temp that it can't so I raised it a couple of degrees. Factory set is 37F, it was set at 33. There is frost on the bottom of the back panel in the freezer and that's why I think it might be the thermostat. I'm open to more advice. thanks

[@carlostrejo8699]

is there a way to determine inside temperature without a heat gun?

[@PartsDr]

Learn the differences between traditional and high limit defrost thermostats here: kzbin.info/www/bejne/n2W2f3idhdSIg7s Learn how to replace a defrost thermostat here: kzbin.info/www/bejne/e3WVdXh4nraJgqc

[@jags132section]

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...

[@PartsDr]

It sounds like your defrost thermostat is probably a high limit safety thermostat. It only cuts out if the evaporator coil gets too hot to prevent a fire.

[@jags132section]

@@PartsDrthanks so much for quickly replying.... I'm not sure..i immersed it in a cup of my faucet hot water 140° left it in fir 10min n still had continuity...

[@PartsDr]

@@jags132section Some safety thermostats have an opening temperature over 140F.

[@kingisingh3879]

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.

[@richeyrich6855]

Thank You!

[@PartsDr]

We are glad you found it helpful!

[@skullhart]

Excellent. Thank you.

[@tavy7200]

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!

[@dr.emilschaffhausen4683]

Could a bad thermostat cause a freezer to be too cold if coils are frozen? My fridge temp is eight on, freezer runs minus 10 degrees F. Damper works fine. Kitchenaid side by side.

[@PartsDr]

No, from our experience the opposite happens when the defrost thermostat fails. The evap coils frosts up and the air stops circulating which causes things to start to warm up.

[@dr.emilschaffhausen4683]

@@PartsDr Thanks for the quick reply. So, with the damper control working I'm left with either freezer thermistor, fridge thermistor or control board?

[@PartsDr]

@@dr.emilschaffhausen4683 It sounds like you are on the right track of narrowing down the problem.

[@russantkowiak4205]

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.

[@PartsDr]

Hi Russ, It sounds like replacing the defrost thermostat should probably take care of your problem.

[@30Thousand]

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

[@PartsDr]

We are glad to hear this helped you find the problem with your refrigerator!

[@adrianflores1662]

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

[@PartsDr]

As long as the temperature rating is correct and it mounts the same as the original, the color of the wires does not matter. Either wire can connect to either location.

[@romiep9557]

How do you test it if the closing temperature is 20 degrees Fahrenheit? Ice water is not enough to lower it to 20 F.

[@PartsDr]

You will need to put it in a working freezer to get it down below 20F.

[@lofenoialof5320]

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

[@jerellluceno1615]

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

[@Schnick74]

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

[@PartsDr]

Great to hear!

[@NIKOSAUDIO1409888888]

One more this model when make defrost they make a big noise like someone try to smash a door you know my wife tells me they have a long time to hear this function

[@rodolfocalderon9861]

Muchas gracias

[@PartsDr]

You're welcome!

[@heidimuller7506]

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

[@PartsDr]

I think your question was answered in this previous comment here: kzbin.info/www/bejne/bZzGp5-kjJ2Ej9E&lc=UgjZLaZ4FiJM6HgCoAEC

[@gregkosinski2303]

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

[@lloydwarden3758]

GE Refrigerator evaporator iced up; the defrost thermostat and heater are both good. What should I check for next. Please help. Thank you in advance

[@PartsDr]

What is the model number of the refrigerator? Use the link below for common locations to find the model number tag. partsdr.com/model-number-locator/refrigerator

[@lloydwarden3758]

That was quick, thanks. The refrigerator came with the house. It's about 26 years old. The model number is partially faded; I could only make out 4 numbers. Since the defrost thermostat and heater are ok, could the problem be in the control thermostat

[@PartsDr]

There should only be 3 defrost components on a GE refrigerator of that age. We would check the defrost timer next.

[@PlayDohMagic]

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

[@harmindersingh-yx8bt]

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.

[@jaiho314]

Singh ji did you defrost the ice first?

[@SxetehakhBettehakh]

I hope you maybe some help. My refrigerator Maytag mtf1895aew Defrost thermostat #63001388 is bad and needs to be replaced. Part is being discontinued by the manufacturer. Leaving no suggestion of any alternative. I have tried every site can’t get it. Can’t get anyone from the manufacturer who can help. Call customer service they are more interested selling the warranty product. No technical support or suggestions available. Now my question is: Can I use a thermostat from other manufacturer that looks similar to one I am replacing. I was told if the temperature of replaced within the same range it is ok. Now how do I know what temperature the bad one and the new one has to be. Please help if you can. Thanks

[@PartsDr]

If the temperature rating is the same, you can use a different thermostat. Follow the information in the video about how to read the temperature rating.

[@fireman5363]

Good video!!

[@PartsDr]

FIREMAN We are glad you found it helpful!

[@davidgriffin7630]

Thank you for the video, it explains how thermostats operate and your replies fill in any gaps in information you were unable to put into the video. I have a problem with the evaporator coils frosting over and fresh food section getting warm on my Frigidaire Gallery French Door Model FGHB2866PFGA, Thermostat has these specs printed on it FR-5 57.2/43.3, I'd like to know your interpretation on what this means with a "/" instead of "-" present. Do you still subtract the 43.3 or could it be it is simply 43.3 temp? On testing, the thermostat opens and closes at about 57.2, i.e. the same temp. I assume this unit is bad since the open and closing temps are the same. I tried to order a new one part no. 5304521781 and literally not a single web or parts stores have one in stock and there is a 2 to 4 week backorder wait, ugh!! I went ahead and ordered one on backorder. My other question is could this thermostat be good, one of those safety ones, and if so, my problem lies in a bad main control board? Your comments would be greatly appreciated, Thank you so much.

[@PartsDr]

57.2C converts to 134.96F which would make this a high temperature safety defrost thermostat if that is the opening temperature. We are not sure what the slash or other numbers means. It sounds like it is probably good from your testing but sometimes they can act up intermittently, so it might be worth replacing still.

[@southernguy35]

He mentioned putting it in ice won't work. Ice is simply water below 32 degrees. It could be 20 degrees, 0 degrees or lower. You really don't know unless you have a thermometer to check it. We had a stupid, stupid supervisor who was trying to calibrate a metal rod thermometer in ice. He had doctorate degree but I could never successfully explain to him why what he was doing was wrong. In his mind, ice was 32 f degrees. Put the thermometer in, let it get cold and adjust to 32. WRONG! Melting ice is right at 32 or 33. He understood if you put a block of wood in a freezer that was zero degrees, when it cooled down it'd be zero degrees. Same on a block of steel. But, put in a glass of water in a freezer that's zero degrees? It'll be ice that's 32 degrees in his mind.

[@SG-gc7mn]

So my thermostat is L140-30F I checked and I have continuity at 139, 112, 80 and 60 degrees. And NO continuity above 140. So that’s means that it’s working right?!?!

[@PartsDr]

Yes, that sounds like it is working properly.

[@geo745don]

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

[@PartsDr]

It depends on the temperature rating of the thermostat. Some should be open and some should be closed.

[@georgezdunic9505]

Instaled $19 dollar thermostat cooling 10-4 temp; 55-35f. defrost vork Awesom video end that`s what was wrong 17 year`s of serice Frigidaire upright freezwr

[@PartsDr]

We are glad you were able to repair your freezer!

[@ammaralyasiri4191]

how can i testin PTC& RELAY REFRIGERATOR

[@PartsDr]

Hi, we currently don't have a video on how to test this part but we are planning to do one in the future.

[@zedcartwright5267]

I have Maytag fridge# BTB2191ARW with discontinued 3 wire defrost stat. Told one is for fan delay. If so two wires green and white on a two terminal plug are for the defrost and fan limiter. Red to heater. Do you know if I can eliminate the fan delay wire and use a two wire stat or if I could splice the old two way terminals together on a new two wire stat so one wire feeds them both? I am not sure which wire green or white is for the defrost and which is for fan? Does it matter which wall recept. terminal they are plugged into. The recepts and terminals look the same I would think they carry the same current as they both just cut off and on voltage. I found a three wire stat on Zoro.com for $40 but I still don't know which wire would go where? Any thoughts?

[@PartsDr]

According to the wiring diagram the third wire is for "defrost testing jig (service person only)". If that information is correct you might be able to replace the defrost thermostat with a 2 wire one and elimate the third wire.

[@garyjoseph2681]

Please help. My thermostat is showing continuity at room temp. Bought a new one and the new one is doing the same. I have a 55-5304521781 frodgidair. Thermostats has FR-5 57/43 on it. Evap coils keep freezing over. Heater has continuity and measuring 30+ olms

[@PartsDr]

It may be normal for it to have continuity at room temperature if it is a "high limit" type of defrost thermostat. Learn more here: kzbin.info/www/bejne/n2W2f3idhdSIg7s

[@mhz2562]

hello my old Defrost Bimetal no any ohm, i test in cold and warm water no any ohm, then i goto buy NEW WP4387503, BUt is SAME.... why??? thanks

[@PartsDr]

It sounds like you aren't getting the thermostat below the closing temperature when testing it. Re-watch the video and follow the instructions from the video. Cold water does not get cold enough to test most defrost thermostats.

[@mhz2562]

@@PartsDr thank, i watch your video and other video in youtube, WP4387503 thermostat L8.9-16.7C, i use ice in water the water is 0C, and i take Defrost Bimetal out of water and no any ohm. i make a video later.

[@PartsDr]

@@mhz2562 Ice water isn't cold enough to close this thermostat. 8.9C = 48F and -16.7C = 2F

[@mhz2562]

@@PartsDr thank, but i don;t have any thing can make -16.7C / 2F to test.

[@izcalirs]

Hi, I have a Kenmore Pro refrigerator (made by Samsung) model# 40140483800 Everything runs but Freezer is not freezing & refrigerator is not cooling. I troubleshot it and results are that compressor will not run. I checked compressor's winding, they checked OK. I disconnected compressor and check for voltage at the connector that comes from inverter board to compressor, and no power. Cleaned evaporator. Replaced all 3 boards: Power Control Board, Main Control, inverter board, and overload protection relay. And Compressor still will not come on. I checked Refrigerator Defrost Bi-Metal Thermostat at room temperature, refrigetator off, and my meter reads ~5 ohms. Any suggestions? Thank you!!!

[@PartsDr]

Typically a bad defrost thermost would not relate to a compressor not turning on.

[@izcalirs]

@@PartsDr based on symptoms described, any suggestions?

[@polgarattila5705]

My thermostat L15-21C what type recommends instead

[@EurekaRecycler]

I have a Sears Freg with a bottom freezer Mo # 596.65932402, Every thing check'd out but we still have ice build up. I do not know how to test the main digital control. How do I put it into Force Defrost mode? Thank you

[@PartsDr]

On this refrigerator we commonly see the JAZZ control board go bad and it causes the compressor continue to run during the defrost cycle. We recommend to replace the JAZZ control board part # PD00004512 and the defrost thermostat part # PD00003405 at the same time to fix the problem. After replacing the parts make sure to manually fully defrost the evaporator coil. Page 37 in the service manual below will show you how to force the defrost mode, but it will not give you the conclusive result. drive.google.com/open?id=0B03VGCZpsUSCN055cmRZbnJhMzA partsdr.com/part/w10503278-jazz-control-board/ partsdr.com/part/67003426-defrost-thermostat/

[@EurekaRecycler]

Is there a way to Force a Defrost cycle? Thanks Alot!

[@PartsDr]

If you click the "read more" at the bottom of my last post, I included information for that. But like I said in that post, forcing the defrost won't tell you the whole story.

[@EurekaRecycler]

OK I see, hold freg door switch down and press Freg temp Down button down 3 times quickly. Than release door switch than F and d will display than press ( - ) again. Well, that did it and goes into defrost fine. . . but why do we still have frost at the freezer vents? If the JAZZ board is bad than does Forced Defrost bypass it? Thank you

[@PartsDr]

Most commonly we see the JAZZ board go bad which causes the compressor to continue to run even during the defrost cycle. Forcing the defrost cycle won't tell you whether the compressor kicks on during the defrost cycle. The best way to fix the problem is to replace the JAZZ board and defrost thermostat and then manually defrost the freezer. Once you do that you should be all set.

[@scotthenderson4376]

I have an old 20+ year old Westing house 22cuft upright freezer that I have to defrost (just done) . It run continuously but stays cold, do I have one of these it it someplace? The sides are hot even though I have a fan blowing on it.

[@PartsDr]

Only automatic defrost refrigerators and freezers will have a defrost thermostat. If your freezer is a manual defrost model it will not have a defrost thermostat.

[@kerrykeyboard]

Awesome! That's what was wrong!!!!!!!

[@PartsDr]

Awesome!

[@jwil-pj2ye]

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.

[@jollyscaria1922]

Bi metal time d forted th,, over lord realy set piont know all one by cheked temperch,,,,wir testng must be comper checking runing eazey but not reparing samll thing semples ok

[@victordemoya2642]

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

[@PartsDr]

We are glad you found it helpful!

[@jeanlourenci]

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?

[@xonerate]

It is Possible that Your Defrost Timer or Switch is Stuck or Possibly Broken. @ the Top Right Corner of the "Fridge" there Should be a Plastic Set Screw, You can turn the Set Screw with a Flat Head Screw Driver. If I am not mistaken you can Turn the Screw "Gently" Clockwise until the Fridge Stops Running. If the Fridge does not Start Running After You shut it Manually, Then there most likely can be a Problem with Your Defrost Switch.

[@Mecambrea77]

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

[@PartsDr]

Yes, this is good advice. We recommend the same thing.

[@andromedaandrade889]

Exactamente, así pasa. Se puede ver en buen estado el termostato de descongelamiento, pero es mejor hacer una prueba con la carga ( resistencia, foco,etc,) para ver si logra encenderlos, obvio también con su respectiva medición del voltaje que de a su salida.

[@andromedaandrade889]

Saludos desde Sinaloa, México

[@bonnieebrown]

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.

[@bonnieebrown]

I would like to add that the temperature rating on both thermostats is L8.9-16.7C. Converting to fahrenheit, that's 48.02-62.06.

[@PartsDr]

Sorry to hear about the incorrect information you were provided before you found this video. We specifically made this video because we had our own customers contacting us thinking their new defrost thermostat was bad when it actually was just bad information that was provided to them on how to test the part. If the refrigerator still doesn't cool down, it is sounding like you may have a refrigerant leak in the sealed system of the refrigerator.

[@bonnieebrown]

@@PartsDr Thank you for your reply. Fortunately, my fridge is cooling down as I hoped. I really appreciate your thorough video.

[@shaneharr9404]

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?

[@PartsDr]

That is correct. The closing temp can be very cold because it is attached to the evaporator coil which gets cold enough to close the thermostat.

[@CommonSenses101]

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.

[@PartsDr]

As long as the temperature rating is the same, it doesn't matter if the temperature is listed in Fahrenheit or Celcius.

[@willfleischauer]

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

[@PartsDr]

Thanks for watching. If you have any tips for us, let us know!

[@yhelyheng2679]

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

[@glennsharp8276]

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

[@PartsDr]

Yes that is a good reading. We would recommend to replace the defrost control board PD00023371 (WR55X10837) and the defrost thermostat PD00023359 (WR50X10090) at the same time. Also make sure to manually fully defrost the evaporator coil before turning the refrigerator back on. partsdr.com/part/wr55x10837-control-board/#model-GBSC0HCXCRBB partsdr.com/part/wr50x10090-defrost-thermostat/#model-GBSC0HCXCRBB

[@BlackCatSyndicate]

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.

[@PartsDr]

All of them that we have seen so far have run off of AC voltage. The heater is only turned on periodically to melt the frost, it does not heat continuously.

[@edwinf9999]

Just what my problem is. I was not sure until I watched this video.

[@PartsDr]

Nice! Glad you figured it out!

[@NIKOSAUDIO1409888888]

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.

[@fred306801]

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.

[@greghanson-w3d]

strong compressor; fridge temp is stable. freezer occasionally ruins food. fan runs, but rarely.

[@PartsDr]

Intermittent problems like these are really tricky to troubleshoot. You usually have to wait for it to act up then start your diagnostics.

[@justincalabrese7774]

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

[@PartsDr]

Nice!!!

[@druiz607]

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?

[@PartsDr]

That sounds like a good reading from what you are describing. You could let it warm up to room temperature to verify that it opens up when it warms up.

[@russellkeith3193]

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

[@PartsDr]

It could be a bad compressor or sealed system leak which is probably not worth repairing.

[@hansoll5126]

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.

[@Tra-V-Logs]

Can the wires of the thermostat be put in any direction? Meaning, is it terminal specific? + -

[@PartsDr]

They can be hooked up in either direction, they do not have polarity with a plus or minus.

[@souhachalhoub2240]

@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 🙏

[@ITIdude1]

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?

[@JohnTheMutt]

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. :)

[@PartsDr]

Awesome! Glad you found it helpful 😀

[@llcane1]

So I did this on on my fridge and the top one passed but the freezer thermostat failed. What was odd was both Fridge and Freezer Thermostat are the same model. Not sure if that is normal. Got another one but it didn't pass the continuity test and beeped cold or warm. Is this test apply to all of them? Making sure before I send it back.

[@PartsDr]

If you check the temperature rating you should be able to tell if it should have continuity at room temperature or not. What is the part number?

[@llcane1]

@@PartsDr The original Part says WR02X12592 60/40. The fridge and freezer are the same sensor number so was going to switch the one I know is good to validate if it is bad. Right now the fridge works but not the freezer. Thanks

[@saleembhutta704]

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....

[@maykaylarobinson3050]

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

[@duruikejohn3844]

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

[@jamesortolano3983]

Great info,thanks Next level!!

[@PartsDr]

Thanks! 👊

[@KervinCalero]

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

[@PartsDr]

Hi Kervin, we have seen this caused by a bad door gasket that is leaking air, a door getting left open, and a clogged/iced up defrost drain.

[@KervinCalero]

Parts Dr thanks for replying! I inspected the gaskets as well and they seemed to be somewhat bent at corners external to the doors. Ill check internal condition. Would you recommend changing out gaskets also?

[@PartsDr]

If you can see where air is leaking past the gasket(s) then they should be replaced. Have you tried just melting the ice to see if it comes back on its own?

[@KervinCalero]

Yes, I have melted the ice multiple times with warm water. Ice slowly builds back up particularly near the opening at the fresh food section where air from the freezer enters. Right now my defrost system seems to be working as I can hear the compressor shut down (and previously verified the heater works). I now have new door gaskets that I'll swap this weekend. In the mean time, how bad is access to the defrost drain? That's next on my check list. Thanks for your help, again.

[@jasonconaway69]

I’m on my second thermostat that reads continuity no matter if it’s been in the freezer or straight out of the package in a 72 degree home

[@PartsDr]

It sounds like you might be testing a high limit defrost thermostat. We have a video that goes over those here: kzbin.info/www/bejne/n2W2f3idhdSIg7s

[@jasonconaway69]

@@PartsDr that’s was the issue. I watched that video earlier, but I didn’t watch long enough to see where you covered the high limit thermostat. Thanks!

[@TheTor]

Hi there. My current defrost thermostat states L175 - 20F. What would the opening and closing temperatures be with those figures? I don't think that 175 degrees would be the opening temp LOL! ;O). Thx for the great video!

[@PartsDr]

Th defrost thermostats with a higher opening temperatures like yours are a safety device in case the main control board and temperature sensor don't properly regulate the temperatures on their own.

[@bevjacquez]

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.

[@PartsDr]

The bi-metal thermostat on Samsung refrigerators is usually a high limit safety that only kicks in if the main control board or temperature sensor fails. It will usually have an opening temperature of 100F+.

[@41point2]

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

[@PartsDr]

On some refrigerators the defrost heater will glow orange/red during the defrost cycle.

[@oliviagrover2662]

My thermostat says LT40-30F. That means according to your video that that it would open at 40 and then close at 10. This can't be right. My new and old thermostat work the same: they are closed at any temperature below about 95 or higher and open above 95 or higher. Neither one open up till they get heated up with a hair dryer.

[@jamesharrison8406]

interesting, so does the bulb itself say L95 0F ? And where is the bulb location...sounds like close to the heat element. On my side by side, the limiter bulb is above the coil some inches, and the numbers are L48 15F. Mine stays closed then 33f and colder, then opens at 48f. it tested good out of the box, although i dont know exactness of the opening temp, its 75 in the house and after several minutes leaving in a good freezer i felt it open, unless the LT means something diffeerent.... but i can say that 30C is 86 F, and 40C is 104F, Sometimes they're written in Celsius. if written in celsius, then it would close at 64 F. There does seem to be a lot of differences in temps these bulbs i didnt know about,,,, good luck,but I'd make sure its an F or a C. My original is in C, and new arrival is in F

[@jamesharrison8406]

im sorry, i see where you already gave the numbers on the bulb. I did notice that it took a while for the bulb to swith or close when i tested it. For test of my new bulb I hung it over the cold moving air right after the fan motor. A thermometer i placed there read 0. it may haave taken longer because the bulb itself was not clipped to anything and so the metal part of bulb was not getting a direct contact read which might take longer. im not sure on that.

[@DeputySage]

Mine is beeping or showing continuity without it being chilled first. I have the bi-metal defrost type (not shown in this video). It does not have any numbers on the probe, but the black cable has numbers. Samsung refrigerator RF26HFENDSR Part NumberPD00002154 Manufacturer PartDA47-00243K Does that mean its bad? Also what is the difference between a Defrost Temperature Sensor, and a Bimetal Thermo Protector? Seems I have both

[@PartsDr]

The defrost sensor is what the control board uses to monitor the temperature of the defrost cycle. This video shows how to test the temperature sensor here: kzbin.info/www/bejne/gGbFqJaqmsp9hK8 On Samsung refrigerators the bimetal thermo protector is used as a safety in case the defrost heater sticks on. We don't have a published temperature rating for the part number you provided but most have a opening temperature around 140F and a closing temp of 104F. This would mean the part would have continuity at room temp.

[@duruikejohn3844]

And is not makeing use of defrost thermostat what is using is defrost ing herter

[@tylerdowns8191]

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.

[@PartsDr]

Our guess is that it will fix your problem. Either way, if it is popped up, it needs to be replaced.

[@tylerdowns8191]

Follow-up a month later - it does appear that replacing the thermostat fixed my refrigerator.

[@PartsDr]

@@tylerdowns8191 That is great!

[@billholder46]

Here’s a ? For you, my freezer will run but when it shuts off it will not come back on and I get a high temp alarm. Is that caused by the defrost thermostat, or the regular thermostat? I thought it was the capacitor and control on compressor and replaced those, though tho old capacitor checked okay. What’s my problem?

[@PartsDr]

That type of problem wouldn't be caused by a bad defrost thermostat from our experience. It could be caused by a bad cold control thermostat.

[@InnovativeShooter]

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.

[@PartsDr]

Some newer GE refrigerators use the defrost thermostat as a high temperature safety and they use a control board and thermistor to monitor the temperature of the evaporator coil to tell the control board when to end the defrost cycle.

[@duruikejohn3844]

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

[@thexxangel]

You saved me money! , thank you very much

[@PartsDr]

That's great!

[@denislafleche2975]

Hi should the coils on my condenser get hot ? I don’t feel any heat from them and my compressor seems to run constantly. But my condenser fan does not turn on ever there is a condenser thermostat that doesn’t seem to be working or maybe it’s not cold or hot enough to close

[@PartsDr]

The condenser coils normally get warm while the refrigerator running as they as exchanging heat with the evaporator coil that is getting cold. If the evaporator coil isn't getting cold and the condenser coil isn't getting warm while the compressor is running, then you could have a compressor failure or sealed system leak. This type of repair is expensive and would need to be done by a professional.

[@akumathelion535]

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.

[@laurenceperkins7468]

Continuity and ohms are functionally the same thing, but the continuity setting is a lot less picky about ranges and often has a beeper attached so you don't have to look at the meter. Ohms will do if your meter really doesn't have one.

[@BillMelater-m6u]

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!

[@PartsDr]

This is the correct defrost thermostat listed for your model here: partsdr.com/part/4387490-defrost-thermostat?model=RT18BKXKQ03 It has a rating of L6.7-14.5C. It is always a good idea to make sure to use the correct defrost thermostat for your model as the incorrect thermostat can cause it to not work properly or in some cases it could be a fire hazard.

[@BillMelater-m6u]

@@PartsDr THANK YOU very much for addressing this issue! You're awesome!

[@craighicks1399]

We're testing our defrost thermostat. At room temperature it's reading 0.00 for continuity. We bought a new one thinking the old one was broken. It also reads 0.00 at room temperature. Visually they both look fine. Is our multimeter not working correctly or are we crazy?

[@PartsDr]

What is the part number?

[@rickeykeeton4770]

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?

[@PartsDr]

Yes it is possible for moisture to get inside the thermostat and cause it to make a poor connection. If you suspect it might be bad, we would recommend to go ahead and replace it.

[@EvendimataE]

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?

[@PartsDr]

It is best to replace the thermostat with an exact match OEM part. Installing one with the incorrect rating could damage the refrigerator or be a fire hazard.

[@fredsapplianceacademy]

appliance.academy

[@kylerbriskey372]

The temperatures on mine says "L140-30F" Is that supposed to be 40-30? or 140-30? So is my opening and closing 40 to 10 or 140 to 110? The second option seems wrong. So I tested my old one assuming 40-30 and mine failed. Ordered a new one, same specs and tested it again before installing and it also failed.

[@PartsDr]

It would be 140 to 110. It is a high limit safety thermostat that only kicks in if the defrost cycle gets too hot to prevent a fire.

[@kylerbriskey372]

Parts Dr thanks for the quick reply. I think that complicates things even more for me.

[@keenanwimbley2143]

Great video. Thank a lot for explaining so clearly.

[@PartsDr]

Glad you found it helpful! =)

[@paulmartello1741]

Is this the only way to test the defrost thermostat? Can you diagnose via the control panel?

[@PartsDr]

This is the only accurate way to test the defrost thermostat.

[@cu0ngpitt]

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?

[@PartsDr]

It sounds like it is working properly from your test results. This thermostat should open after warming up to 58F and close when it cools down to -14F.

[@cu0ngpitt]

@@PartsDr Thanks I made a mistake on the conversion. Mistaking C for F. I believe you are right, thermostat is okay. Do you have any videos on how to test my defrost adapter controller?

[@jefferyantoine5551]

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?