Bottom line: life sucks when you don’t have a fridge. They’re incredibly important and painfully expensive to replace. Here are some tips and tests for Dometic RV fridge troubleshooting before hitting the service centre if your fridge is on the fritz.
Don’t you just love when you buy groceries and then they all spoil because your fridge decided to stop working? It’s my favourite. Not. We recently experienced a long, drawn-out fridge repair that was super stressful and held us back from travelling until we got it sorted. After tons of manual-reading and YouTube-watching, we tried about every different test we could find to try to isolate our issue and figure out why our Dometic fridge isn’t cooling. We have a Dometic refrigerator (RM 2351) and the manual makes troubleshooting quite simple: if your fridge stops cooling, take it to a service centre immediately. How helpful… With the wealth of information available on the internet these days, it’s worth at least giving it a shot before taking it to a professional. Save yourself some cash and maybe even learn something new with our guide to troubleshooting a Dometic RV fridge.
Full disclosure, we are by no means technicians. We’re just a couple of folks that did a ton of research, spoke to experienced professionals, and fixed our $1200 fridge for $7. Also note that this list only applies to absorption fridges. Do yourself a favour and watch a short video to understand how these things work so you can better understand where your issue might lie.
Before getting into the more technical stuff, check the basics. Absorption fridges rely on gravity to function properly so make sure that your fridge is always level. Unscrew the back panel on your fridge’s vent outside of your van/RV, remove the control board cover and check your fuses. Side note: apparently it’s quite common for wasps and other insects to build nests in these vents, especially if you’re stationary. So be careful when removing the vent. Ours has two glass fuses, a 3A and a 5A, so be sure to inspect both.
Next, check to make sure that your 120v outlet works. When plugged into shore power, plug something else into it (i.e. a string of lights, a cell phone charger, etc.) or get your multimeter and check for a current.
Lastly, make sure you have propane and that it is in fact, on. If you’ve solved your problem by this point then rejoice! Your RV refrigerator troubleshooting days are behind you and you can move on to cool, refrigerated happiness.
Also, remember that these things take a while to cool – 6 hours is the recommended time by Dometic to test the temperature. As the technician told us, every time you open the door to the fridge, you lose 1-2 hours of cooling.
CULPRIT: LP GAS (PROPANE)
First, bypass the LP system by putting your fridge on auto while hooked up to shore/AC power and see if it works.
Test the propane by removing the fridge’s vent cover while the fridge is off. Remove the metal cover under the flue tube. Make sure that your fridge is on gas mode, not auto, and have someone turn it on while you listen for the sound of the propane igniting. Once it lights, observe the flame – it should be a nice clean blue flame. If it’s not, there could be an air bubble in your line so bleed the line (turn propane off and light stove until the flame goes out and there’s no more propane in the line before turning the propane back on) and try it again.
Next, clean your flue and flue baffle. These are very funny names for very important elements. The flue is essentially the chimney of your fridge and the flue baffle is a twisted metal piece that sits inside the flue tube. These should be cleaned periodically; buildup and dust can affect the performance of your fridge. Also, please don’t be silly and test for propane with an open flame – you’re just asking for it.
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CULPRIT: ELECTRIC ELEMENT
First, bypass the 120v system by putting your fridge on gas while disconnected from shore power so it will only use propane and 12v DC power and see if it works.
With the fridge off, switch back to auto and make sure that you’re connected to shore/AC power. Turn it back on and check if the boiler gets warm. If it doesn’t, you may need to replace your electric element or always run on gas mode.
CULPRIT: CONTROL BOARD
Turn your fridge and propane off and disconnect from 12v and 120v power. To test if your control board is shot, which is very common and super easy to replace, you’re going to need to bypass it. Find an appliance you have lying around that no longer works (or get something from the dollar store) because you’re going to need to steal the plug from it. Cut the wire on your dud appliance (leave a foot or two in length) and locate the wires that power the electric heating element, which run from the boiler into the control board. Unplug them from the control board and you’re going to need to hardwire them to the loaner plug that you cut off from your spare appliance. Polarity does not matter so you don’t need to worry about which wires are positive or negative.
With your fridge now having a direct plug that doesn’t require the control board or fuses, plug it into your 120v outlet while connected to shore power. Alternatively, you can plug it directly into the shore power source. If it gets cold after a few hours then you’ll need to replace your control board. In theory, if your control board is broken then your fridge should be frozen if you leave it overnight. These run about $100 but are as simple to replace as unplugging your current wires and reconnecting them to the new board. Here’s a link to a video to watch it being done.
CULPRIT: COOLING UNIT
First, check to see if there’s any crusty yellow liquid inside or anywhere on the back of your fridge. It’s possible that ammonia is leaking and therefore, the cooling unit can’t operate properly and needs to be replaced.
Next, since you’ve been such a good reader and attentively watched the video on how an absorption refrigerator works, you know that the cooling unit is powered by a series of chemical state changes. The only way these state changes can occur is if the tubes are clear for the ammonia to flow through. It’s possible that there is a blockage, which is either past the point of no return or can be “burped” by turning the fridge upside down. Sounds odd but this is an old school trick that can work shockingly well and costs no money – AKA the perfect solution.
You’ll need to make sure your propane and AC/DC power is off and then disconnect your fridge completely. Take a photo of the back of the fridge first so you can see where all your connections go. Then label and take photos of each piece as you unhook them so you can easily hook them back up in reverse order. Remove the fridge from its housing inside of your RV and carefully turn it on its side and then on its head and listen for the sounds of liquids flowing. I’ve read a lot of mixed information about how long you should leave it upside down and there doesn’t seem to be a definite answer. We rotated it 2-3 times consecutively and then left it upside down (and level) for about 3 hours. We could hear the liquids moving through the tubes as we turned it so we knew that was a good sign.
After 3 hours, turn it right side up and leave it to sit overnight before turning it on. It’s important to leave it turned off and sitting upright for longer than 3 hours to let everything settle again. Carefully hook everything back up, turn on your power and propane and turn the fridge on. Test the temperature in 6 hours. A cooling unit can be replaced at home but is a little messier than upgrading other elements. If you can find a replacement at a decent price then go for it but be aware that these are usually $500+.
Most RV fridges are equipped with a clip on the back fins that allows you to control the temperature slightly. The sensor inside that thermostat is called a thermistor. In a nutshell, as the temperature drops, the thermistor increases resistance and sends more ohms through to the control board. Once it reaches a certain temperature (usually about 1°C/34°F), it’ll reach an ohm rating (usually between 7-10k Ω for Dometic fridges) that sends a signal for the fridge to turn off. It won’t come back on until the temperature rises to a point where the ohm rating is below the shut-off level and requires cooling again.
Anyway, if the thermistor is broken then either A) your fridge will cool slightly then stop because it thinks it’s cold, or B) your fridge will always be frozen because it thinks it’s warm. To test your thermistor, unhook it from the control board (follow the wire coming out of the back of your fridge beside the drainage tube) and turn your fridge on. Within 6 hours, it should be cold and if left overnight, it should technically be frozen depending on what your ambient temperature is. You can replace the thermistor by buying the kit from Dometic, buying a temperature control dial with a built-in thermistor, or buying a generic thermistor from an electronics store. A generic thermistor will require connecting the wires to those of your broken thermistor in order to reuse the plug specific to your control board.
This ended up being our culprit, so we bought an epoxy coated thermistor that came with a tiny resistor and wired that into our existing plug. You must make sure that it is an NTC thermistor (negative temperature coefficient) so that the resistance increases as the temperature drops. The ohm rating is key here, ours is 10k Ω, which is a pretty standard one. Standard, but not suitable for this purpose (see below).
*JAN 2019 UPDATE:
Although the 10k thermistor we swapped in got our fridge working again, now that it’s winter and we need far less cooling power, we’ve noticed that the fridge never shuts off. As mentioned above, the thermistor should send a resistance of 7-10k when the fridge reaches temp telling it to turn off. Turns out the 10k resistor isn’t our answer because it doesn’t send that ohm rating until it reaches +25°C, AKA not a temperature you ever want your fridge to be. With some research, we’ve found that you’d actually want to buy a thermistor with a 2.8k rating instead of 10k (data sheet for further reading here and product link here). Send us a message if you find yourself needing to replace your thermistor with one of these bead ones and need some direction on how to do so. You’ll need to solder it onto your existing wire and coat it in epoxy or liquid electrical tape to assure it’s waterproof.
All in all, RV fridges can be pretty intimidating but are really not as scary as you may think. It’s worth taking some time to troubleshoot your Dometic RV refrigerator on your own before taking it in for repair or replacing it altogether. Just make sure to be careful when dealing with all electric and gas connections and to give your fridge enough time to cool down. They are said to take 12 hours to fully reach temperature but factors like the outside temperature and humidity can slow this down and leave your fridge working overtime. The ambient temperature in an RV parked in the desert is going to have a huge effect on the performance of the refrigerator in comparison to a fridge sitting in a 10°C/50°F room. Be patient, be careful and keep that fridge level!
Hi, this is the most comprehensive and helpful stuff on a caravan fridge I have seen.
believe me I have been researching this topic for a while so as not to have to do the replace the fridge bit like everybody has recommended to me.
Thanks very much for this.
Thanks so much Bill! We found the same thing when trying to fix ours and wished there was just one resource explaining everything. Glad it was helpful. After a lot of research, we successfully fixed our fridge for $7!
Wow, best instruction for anything I have searched on the net for, pictures descriptions and video, all clear and precis. I’m now armed and ready for action, if this guidance doesn’t fix my cooling problem then its time for a new fridge. You rock!!!
Fantastic Gary! So glad to hear you found it helpful!! Hope you got everything sorted 🙂
My high temp limit board turned my Norcold off last night. Checked different sources and diagrams and found I could bypass this board easy enough but my question is, is the board bad or is the temp inside the boiler too high?
Unfortunately we don’t know much about these Norcold units. But, if it were us we’d try bypassing the board to see if we can further diagnose the issue. Other than that we wish we could help you more. Good luck!
Yes thank you very much I agree very informative very straightforward pictures excellent for Laymen like me looked for a long time though to find yours. Thanks again
Happy to hear that, Mike! Glad you found this helpful.
Where did you get your control board from
We didn’t end up having to replace our control board but I would definitely contact Dometic first and see if they can send a new one out to you and then check to see if ebay or amazon would be cheaper.
Thank you for taking the time to put together the most informative post I have ever seen pertaining to RV refrigerators. I have searched articles and watched videos and no one has put together a more detailed description on troubleshooting all aspects of the units.
So glad you found it helpful!
Terrific article! Our nearly new (but off warranty) Dometic frig does not cool on gas or electric settings. The cover to the boiler cover is warm to the touch when set on gas or electric. My question is how warm is normal; does this suggest there is a blockage and no circulation of coolant? Also, do you know whether trying to operate the frig while parked on a significant slope could result in a blockage? Thanks again for your guidance.
Thanks for checking out the article! Sorry about your fridge troubles.
These fridge systems should only be run while level. If you’re not level the fluid can’t get through the system and they won’t work.
If it’s feeling warm that’s usually fine but make sure you have a flame going on your pilot.
The main thing you should try is burping your fridge. We have a full outline on how to do that in the article.
It’s a little annoying but works well if you have a blockage.
I have a question for y’all. on my control board but there’s a little black box that is clicking constantly any idea whatsoever what it could mean it is the black box on the left hand side of the control board by the 3 amp fuse. if y’all could come up with something for me I’d sure appreciate it I’m a daisy-fresh rookie at this
Not 100% sure what you’re referring to but if you want to pop us an email with a picture and even a video with some sound. We can take a look and see if we can point you in the right direction. firstname.lastname@example.org
I want to remove my rv fridge and you provided a lot of useful information that I need. Thanks so much!
Yay! Glad to hear that Natalie. Good luck with the removal.
yeah! I also find some information in here. I think it useful for guys.
Thank you for this tutorial. This was the one who finally let my fridge come to the point of Coming alive! And also. I had to do the burping thing, now please people who fridge does not start working even if you turn around your fridge. Then start smacking thise pipes gently with screwdriver or whatever. This was the thing that got my fridge starting… so happy!
Awesome – glad you got it running again!
What a blessing! 1000 miles from home. Had enough tools to do your tip over routine. I was maybe a little impatient time wise but come morning ICE. THANK YOU.
It’s a pain in the ass to do but burping the fridge seems to do the trick! We’re so happy you got it sorted!
Our 3 yr old Dometic RM 2551 just failed yesterday- apparently the door wasn’t fully closed and the fridge defrosted- but now won’t restart. Airstream is parked and level, boiler is hot on both 120VAC and propane- but after running it overnight it still won’t cool. Any ideas on a failure mode or if it can be resuscitated? Very good tutorial- hope mine doesn’t need burping!
That’s always the worst!
Are the tubs on the back getting warm or hot?
Have you checked the fuses on the circuit panel to make sure they haven’t popped?
If the fridge was working too hard with a door open it’s very likely you blew a fuse.
When we burp a fridge it’s usually still getting a little cold so the burp gets the fluids moving if any sediment has built up in the tubes.
What a great article ! Thank you. I do seem to have a very specific problem that I’m not sure was covered. My freezer portion is a -5 degrees F…certainly very cold. however my fridge, even after 12 hrs doesnt go below 60. I’ve tried gas and electric…same result. Id greatly apretiate your advise… its a 2 year old unit , Dometic RM2351… looks similar to yours.
thank you in advance,
please email me if you have time .
Sorry to hear about your fridge troubles.
We’re certainly not pros at this stuff but we’ve dealt with a bunch of issues with our own fridge.
Look into the placement of your thermistor and make sure it’s sitting in the right spot.
And when it doubt taking the fridge out and giving it a proper burp has done wonders for us in the past.
So, I unhooked my propane to go fill tank and left my Dometic 3way fridge on gas when I left.
Rehooked full tank and now fridge will not draw gas, will only flash red.
Switched to battery for a bit and back, nothing. I’m off grid.
Reset breakers, nothing.
Any thoughts please and thanks!!
Red flashing lights are never a good sign.
I know it might seem silly but is your gas tank turned on? I’m sure it is but we have to ask.
If you left the fridge on while the gas was disconnected it may have drawn air into the system and this is causing pressure issues.
Other than here’s a checklist we’d go through:
– Check to make sure gas is connected securely and turned on properly.
Turn your system off completely, disconnect the gas and then reconnect the gas and start up the fridge. (Does your gas work on your stove?)
– Check to make sure your wiring is hooked up correctly and that you’re getting proper voltage through the line.
– Check to ensure all the fuses on the control board are still working.
– Turn off the unit, disconnect the power wiring then reassemble and turn the unit back on.
– Try burping the unit to see if this helps. (This isn’t usually a fix for this sort of problem.)
– Lastly, I would say your control board might be fried while it was trying to keep itself going when the gas wasn’t hooked up.
How many times is the red light blinking? This can give you a good indication as to what the error is.
The Burping did the trick for me 🙂
Thanks a lot Awesome guide.
Yay! So glad to hear that Mauro.
First love the troubleshooting, def way better than try to distinguish the language they speak in a service manual. So ive tested everything that you have shown me how to test, ohms the element and it ohms out fine but hit a wall so I figured id bypass the board, by the way on LP the boiler heats up really hot , the heat shield around cannot be touched but that is the only thing getting hot. None of the lines top or bottom are warming and the fluid reservoir isn’t heating up either. Sooo bypassed the board and after about 2-3 hrs it tripped the breaker in my garage. This is the same outlet I use to run my big air compressor so I figured I could turn it off and shouldn’t have a issue with too much amperage also used a heavy duty extension cord. I hear no noise from the coils or boiler and definitely no cooling whats so ever in the fridge. I tried again because it has been really hot outside lately around 98 with a index of 108 so i put a small fan blowing in towards the unit and made sure i could feel it coming out the top. Still tripped the breaker in about the same amount of time. Any suggestions besides the burping? Because if this junk is removed it will not go in, ill find a regular fridge to stick in there.
Hate to say it Tim but it sounds like it needs to be burped. If you’re still getting a good flame but the heat is not getting into the lines then there might be a blockage – even just an air bubble. That could also explain why it tripped your breaker because it’s overworking itself.
At least if you go to the trouble of removing it and burping it and it gets going then you can sell it! Good luck
Hello. Very informative and helpful article as others have mentioned. My fridge was working this past weekend until we unplugged from shore power and came home. Now the fridge won’t turn on. No lights or power. The eyebrow control board has no power so when I press on/off, no lights come on. I used a multimeter and get 118v on both ends of the control board when connected to shore power. I replaced the control board and still nothing.
However, I tried your trick of connecting the electric heating element straight into shore power and the fridge/freezer are cold after 4 hours (Which means bad board, but I just replaced both the control board and the eyebrow board). ??♂️
Hmm that’s definitely a weird one. The two of us just brainstormed over this and the only things we can think of would be to
1) replace all your fuses – sometimes those glass fuses look fine but might have a crack or something not noticeable that’s stopping the current
2) follow all of your wires coming into the control board to make sure there is no damage and they’re not loose. Obviously your AC wiring works if your fridge is cooling with the control board bypassed so there could be a chance that another wire came loose or is damaged.
Lastly, have you tested it on LP gas? Hope you can get it sorted!!
So I had my camper plugged into electric and it got cold like it should be. When I changed over to gas for the weekend because where I was going didn’t have electric hookup, my fridge wouldn’t get cold. You could see the flame when the gas was on. When I got home, I plugged back into electric and still not getting cold. I replaced the Thermistor, but it didn’t fix the problem. Do you know what I could do to fix this problem? I am going camping this weekend and would like my fridge to be working again. Camper is only 2 years old.
Is there a chance you blew a fuse while switching back and forth?
I checked the 5 amp glass fuse on the circuit board and have continuity. Did an ohm test on thermistor and it tested good. Old thermistor that I thought was bad even tested good.
Hmm, are you getting a nice blue flame when on propane? The only thing we can think of is to clean your flue baffle and bleed your propane line because there could be an air bubble. As for it not working on electric now, that is pretty strange. How long are you giving it to cool down? Maybe try leaving it overnight to test. Hope this helps – keep us posted.
I have left it on for couple days. Yes there is blue flame when gas is lit. The heat chamber is hot to touch. So it’s heating that. I have had it plugged in for 4 days at a time and haven’t gotten any colder.
Well, it’s not a fun process but it sounds like burping it is the next thing to try. If your gas and electrical is all working properly but it’s still not cooling then it’s definitely worth trying to rule out that your cooling unit isn’t shot.
We’re crossing our fingers for you that that’s your ticket!
It wouldn’t be the control board would it?
It definitely could be if you want to try the control board bypass before taking the fridge out
While testing the circuit board by hard wiring it, do I have the fridge turned on?
You would plug it in and then power it on from the eyebrow board on electric mode.
This is the best resource in all of the web for absorption fridges. I’ve looked for months and this has it all – operation, maintenance, troubleshooting, explanations, great pictures, ideas, and important details. And I am a 8 year naval nuclear mechanic that specializes in R-114 refrigeration units. Thank you for putting this excellent page together!
Thank you so much! What a compliment, that totally made our day. Glad you found it helpful!
I have left it on for couple days. Yes there is blue flame when gas is lit. The heat chamber is hot to touch. So it’s heating that. I have had it plugged in for 4 days at a time and haven’t gotten any colder.
One thing I never see discussed is how level is level enough? do you have any answer?
So sorry for the late reply on this Steven. To be honest, the tolerance for how level is pretty slim. We’ve found to be ok on a slight incline for a night or two but if you’re staying anywhere longer, you want to be as level as possible. Blocks help.
So to answer your question—strive to be perfectly level. Slight incline on either side is ok for daily operation but no good for long term. If you’re on any sort of steep incline for an extended period of time, it’s best to turn your fridge off or you might have to burp it afterward.
Hope that helps!
I have a model RM2652 refrigerator that is getting too cold at approximately 19 degrees F. I have checked the thermistor and it states that it should read 8 to 10K ohms in ice water. Mine is reading 23K ohms. I would think this would be plenty high to turn off the fridge. I’m not sure if I should replace the thermistor due to the high reading or whether the control board is where the problem lies. This is while running on 110 VAC. Any suggestions?
That definitely sounds like you could have a thermistor issue. If you have an electronics or robotics store in your area, we’d suggest picking up a small bead thermistor like this and testing it out. Because your ohm reading is so high, it’s not sending enough resistance to signal for your fridge to turn off. This is the same situation we had with our 10k resistor.
Good news is it’s a cheap and easy fix! Definitely a good place to start before swapping out the control board.
Good luck and let us know if you have any other questions.
Thank you for sharing what you have learned while researching these over priced short lived necessity’s .I am not where my RV is at currently but mine is very close to the one shown in your example’s that you call “ours” one question I have is that there is a noticable difference in the board . I too have two fuses except mine are the two prong plastic type fuses one Is a 5 amp or a 3 amp I can’t remember but the other one is a 30 amp that is a big difference then yours does that sound right? My problem is besides not working the gas clicks and I took the cover off and it lights for a second and goes off then lights for 2 seconds and goes off and keeps repeating the same thing one then two then one sort of like it is sending an sos or something I was curious about the 30 amp fuse . Tomorrow I will try and clean the flu and baffle.oh one more thing I found a blue wire not hooked to anything and can’t see where it would go I think the one end was hooked to the board at j1 location and the schematic says a test wire or something like that. I just bought the 32 ft Cardinal 5th wheel and when I opened the back there was only one fuse in the back but I can see right next to it a place for another fuse and on the board it says 30 amp .I don’t know why he would had removed the fuse . So I don’t know if I am suppose to have a fuse there or not. Anyways if there is something I said that rings a bell with you please don’t hesitate sharing it with me. Thanks for the help you provided at least it gives me some starting points it’s a really nice fridge with the all wood front and I don’t want to remove it and put the small electric fridge that everybody goes with at some point. But these RV fridges are a real racket I have seen so many that ten years later they aren’t even worth scrapping .it’s a real racket they get away charging so much for them.