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Kahoona

Dometic fridge won't run on electric.

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We have a Dometic RM1350 4 door fridge. It won't run on AC. Goes right to gas.  I have the shop manual and have run some troubleshooting.  I have verified that we have  :

DC power to lower board.

Proper operation of upper boards and connection back to lower board.

AC to loser board.

working heating elements

The AC sensing circuit is not turning the power on when Auto is selected. It may not be sensing AC  incoming or it is not switching it on.  On switch causes it to start but it will only start in gas. It cannot be set to auto, it momentarily blinks the indicator for auto then goes straight to gas. The upper and lower boards have been replaced as well as the on/off board.  Anybody else run into this?

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Welcome to the Escapee forums! It sounds like you are off to a good start. The fact that it works properly when on propan tells me that all parts of the control circuitry are working properly since both energy sources use the exact same controls. What you haven't mentioned checking is the two fuses on the main circuit board. The 3a one is for 12V and since the controls work we know that it has to be good but the 5a fuse is for power to the 120V heater and if it is open you would have exactly the symptoms that you have described. 

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You need to check the electric heater element for the fridge.  You will need a volt-Ohm meter to check the resistance or open circuit on the heater element.  An alternate method, if you can work safely with electricity, is to disconnect the electric heater element and wire it directly to  120 Volt cord and plug it in and let it operate overnight.  If the fridge cools in this by pass mode, the heater element is OK.  If good.  If there is no cooling, the element is bad.

Ken

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15 hours ago, Darryl&Rita said:

While you've got the meter out, confirm power at the plug.

EXACTLY, to work on 120 VAC it needs "power at the plug",,,,,,,,,,,,,,,,, 120 VAC power to the control board,,,,,,,,,,,,,,,,,,,,,,,120 VAC to and through the onboard fuse as Kirk mentioned,,,,,,,,,,,,,,,,,A good conductive NON OPEN correct resistance heating element,,,,,,,,,,,,,,,Of course the control board needs to function properly (having a good 12 VDC supply to it) to sense the presence of 120 VAC and send power to the heating element via the fuse...........

Late PS:  In the event the 120 VAC source fuse (to the heater) is blown BEFORE you replace it check the resistance of the heating element line to line and also insure NEITHER lead is shorted to case/frame/ground…..

 John T

Edited by oldjohnt

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He did indicate that he has 120V to the lower circuit board and also that he somehow checked the electric element. On the other hand, if he as come back at all, he has not signed in so all of our efforts may be a waste of time. Kahoona, if you are reading this, how about signing in to let us know where you are on the problem?

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On 10/12/2019 at 9:04 AM, Kirk W said:

He did indicate that he has 120V to the lower circuit board and also that he somehow checked the electric element. On the other hand, if he as come back at all, he has not signed in so all of our efforts may be a waste of time. Kahoona, if you are reading this, how about signing in to let us know where you are on the problem?

I am so sorry! I thought than nobody replied because Outlook put you in the Spam folder. They do it to all of the most important messages so I should have looked.   Probably too late now.

  Checked the element resistance with an ohmmeter. Checked everything else suggested and all is working except the AC mode. I did something I read about and fed the heater directly bypassing the board and it worked (at least as well gas does anyway) so I know it is capable of functioning. I am frustrated because everything points to the board but here I sit with three boards that I replaced and every time I still have the problem. I hate to go get a fourth $300 board. I seem to have few options.

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2 hours ago, Kahoona said:

Checked the element resistance with an ohmmeter. Checked everything else suggested and all is working except the AC mode. I did something I read about and fed the heater directly bypassing the board and it worked (at least as well gas does anyway) so I know it is capable of functioning

Thanks for the feedback...…….Okay from what you say it appears the AC heating element itself  is okay and not shorted but if you tried three boards and still have the problem ??????????????????

1) You stated   "DC power to lower board"  Have you checked the actual voltage ??? If too low it can cause erratic behavior, does it help or matter if you're plugged to shore power or not which can raise that voltage ??

2) You stated " AC to loser board" and now what you posted makes it appear the heating element itself is okay and not shorted.

3) Can you track down and trace out the circuit (just 2 wires) and connections (plugged in and good n tight no broken wires) to the heating element ???? If its bad or the connection is bad in that cable/circuit such would explain how even a good board isn't allowing 120 VAC operation.

4) Again the AC portion requires 120 VAC at the receptacle where the fridge plugs in plus a good non blown AC fuse on the board, sure its getting 120 VAC ???  If its not sensing the presence of 120 VAC via the receptacle and plug and cord it will want to switch to LP Gas. Insure there's no tripped AC breaker (or bad open wiring)  feeding the branch circuit into which the fridge is plugged and that receptacle has 120 VAC plus the plug and cord to the fridge is good. She cant work or sense 120 VAC if none is there.

 John T   Runnin out of ideas here, if all else fails you may have to resort to reading the manual lol

Edited by oldjohnt

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4 hours ago, Kahoona said:

I did something I read about and fed the heater directly bypassing the board and it worked (at least as well gas does anyway) so I know it is capable of functioning. I am frustrated because everything points to the board but here I sit with three boards that I replaced and every time I still have the problem.

In case you do not have one the RM1350 service manual is available on the website of Bryant RV Service.

In reading your first post again, it seems that the auto function will not select 120V mode? Page 16 of the linked manual gives some information and one of the items to check is that the resistance of the 120V heating element should be 34.3Ω. Have you tried using an extension cord to get 120V from another source outside of the RV and connect the 120V plug of the refrigerator to that, just to eliminate any problem in the RV120V supply? It may not prove much but it would eliminate any problem outside of the refrigerator. I would also trace the 120V through the lower circuit board, starting by checking for it between pins J5 & J6, then move to the 5A fuse and measure from neutral to each side of that fuse, which should show 120V to each side of it. I also like to use a jumper across the fuse holder in place of the fuse just as an alternate way to verify that it isn't causing a problem. The auto 120V detection is after the 5A fuse so if it should be a problem it will prevent the selection of 120V. Page 25 of the linked service manual shows a schematic of the refrigerator. Section 11 found on page 40 of the service manual is a set of diagnostics that may be helpful. I have no practical experience working on this model so reading the tests is the total of my knowledge of them. 

It seems highly unlikely that you would have 3 bad circuit boards and most suppliers will not allow you to return one so I'd go a long way before buying a fourth. 

 

Edited by Kirk W

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Thanks for the reply. I have  not tried jumping the fuse yet so I will. Thanks. I have tried the rest though. Yes. I agree that 3 bad boards would be unlikely but 2 licensed experienced mobile techs said that that had to be the problem so I kept trying. One of the 3 was used too so it could have been bad for  all I know. I agree about tracing the 120v through the board  which I thought might be beyond my ability.  I have repopulated and overhauled 70's audio boards  but I had diagrams and reading lists.  Looks like I will do just that. Since I have power to the fuse I can start there. I have 2 used boards I can bench and work with safely here in the campground.

  I do have the manual which I printed and have nearly worn out :D.  I have done every test in the manual twice to be sure. I am using Diagram RN1350M since it has the same components as mine. mine id an Auto Lock but has had the lock disabled and the wires taped off and stuffed inside.  When the fridge is turned on the lock still makes a clank. Any way that the defeated lock could affect the element?

 Believe it or not I do have another new board but I am reluctant to risk it  in case something in the system breaks it.  We were traveling from The Keys to New Jersey and then the outer banks buying 20 lbs of dry ice per day while trying to get a board to arrive at one of our stops on the day it was promised. or a tech who could fix it.  I wound up with extras. Once I replaced the igniter the LP gas worked and things got easier. LOL RV's are fun. Full timing is going to be even funner!

Thanks.

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19 hours ago, oldjohnt said:

Thanks for the feedback...…….Okay from what you say it appears the AC heating element itself  is okay and not shorted but if you tried three boards and still have the problem ??????????????????

1) You stated   "DC power to lower board"  Have you checked the actual voltage ??? If too low it can cause erratic behavior, does it help or matter if you're plugged to shore power or not which can raise that voltage ??

2) You stated " AC to loser board" and now what you posted makes it appear the heating element itself is okay and not shorted.

3) Can you track down and trace out the circuit (just 2 wires) and connections (plugged in and good n tight no broken wires) to the heating element ???? If its bad or the connection is bad in that cable/circuit such would explain how even a good board isn't allowing 120 VAC operation.

4) Again the AC portion requires 120 VAC at the receptacle where the fridge plugs in plus a good non blown AC fuse on the board, sure its getting 120 VAC ???  If its not sensing the presence of 120 VAC via the receptacle and plug and cord it will want to switch to LP Gas. Insure there's no tripped AC breaker (or bad open wiring)  feeding the branch circuit into which the fridge is plugged and that receptacle has 120 VAC plus the plug and cord to the fridge is good. She cant work or sense 120 VAC if none is there.

 John T   Runnin out of ideas here, if all else fails you may have to resort to reading the manual lol

1-Yes. It is hard to do because the uppre board and switch board seem to be coated  with something that makes contact difficult but I got over 12v on every  contact and  continuity checks on the control buttons.

2-"loser board" eigh!"  Typed what I was thinking. :D. Heating element tests at proper resistance and is at this moment powering the fridge  having been jumped directly from the input wires to J5 and J6. This demonstrates that the hearer is good and the power is good. 120v at the outlets. 

3- Checked all 3 fuses, Yes 120, even tried an extention cord to the house to power at J5&6.

John- ROFL  I hear you! I already got the manual and have literally worn the printed copy out! I had the fridge out to  fix the badly done install that blew heat up on top and I did all of the maintenance, even the baffle replacement, flue clean, all tests, remaking the enclosure, taping seams and more and it still can't run right or make ice cream hard! Shoulda kept the old gasses class A with the 2 door Dometic. Excuse the rant but I want you to know I am not just saying yes to every question. I have traced the wires to every peripheral device to see if wires are crossed of something is shorted. I will start on tracing the AC through the lower board if I can like Kirk was saying.  The plumbing sucks but I think it works as well as any 1350 so somewhere  there is a cracked wire or bad module that is getting in the way. I'll keep you posted. Did I mention that this is a 2008 with 23k on it so there have been all sorts of trouble with the rubber bits. I don't know if sitting for years hurts dometics either.

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3 hours ago, Kahoona said:

Did I mention that this is a 2008 with 23k on it so there have been all sorts of trouble with the rubber bits. I don't know if sitting for years hurts dometics either.

What make/model is the RV? Sitting can impact some things but I can't think of any reason sitting would account for the problem that you have. It seems that the lower circuit board isn't sensing the 120V, even when we know that it is there. The manual seems to be saying that it should detect power and change from gas even if the voltage applied is less than 100V, so it does appear to point to the board, which is difficult to believe. If you do get another lower board, before you do so check to see if there is one available from Dinosaur Electronics to fit your Refrigerator. I have found them to be superior to the OEM boards, cost less, and they have a better warranty. You can get them through this dealer.

Did you happen to check the upper board per page 21 to be sure that the auto feature is actually turned on? 

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22 hours ago, Kahoona said:

Excuse the rant but I want you to know I am not just saying yes to every question

Kahoona, I hear you. Sooooooooooo you have checked to see if 1) There's 120 VAC getting to the board,,,,,,,,,,,,,,,,,,2) The fuses on the boards are okay,,,,,,,,,,,,,,,,,,,,,,3) Theres good 12 VDC for control getting to the board,,,,,,,,,,,,,,,,,,,,,,,,,,4) The heating element itself is okay and works if power is jumper to it,,,,,,,,,,,,,,,,,,,,,,  SO SINCE 120 VAC IS PRESENT ITS EITHER NOT SENSING IT (board function)  OR ELSE NOT PERFORMING THE AUTO SWITCH FUNCTION (a function of front display panel and/or rear board, see below). Its just hard to believe three rear control boards are all bad.

 There are wires and connectors from the front display panel down to the rear board, so if its possible to get to them I would next concentrate my troubleshooting on that wiring and connections or else consider those display panel issues described below on the web page I cite. Since three boards act the same I'm starting to doubt its a board problem and you have pretty well eliminated the other things I asked about above. It would be nice to have another display panel in case that's the problem  (Yeah right who has one of those laying around lol)

Although this concerns ARP Installation:  https://www.arprv.com/dometic-rm1350.php

NOTE since you don't have the ARP none of this may apply I didn't take the time to study it carefully so take this with a grain of salt !!!!!!!!!!!!!!! REGARDLESS with three boards all acting the same I wonder about the display panel and its wiring as a possible cause ??????????????? 

It (if it applies and not only ARP) has some good info regarding troubleshooting and especially list Error Code EO as :      ""No communications between the Dometic control board in the cooling unit compartment and the front display panel. Check for bad wiring connections, power down and back up. Control reverts to full automatic operation.""   If you look at the above web page under DIAGNOSTIC MODE it discusses COMMUNICATION FAILURE but it appears it would revert to full automatic operation BUT YOURS ISNT REVERTING TO FULL AUTOMATIC (but you don't have ARP)  which shoots all this down grrrrrrrrrrrrrrrrrrrr

Oh well check out the web site Diagnostics it may help or confuse you even more or isn't even applicable with not having ARP.

John T   Running out of ideas here  

Edited by oldjohnt

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29 minutes ago, oldjohnt said:

Kahoona, I hear you. Sooooooooooo you have checked to see if 1) There's 120 VAC getting to the board,,,,,,,,,,,,,,,,,,2) The fuses on the boards are okay,,,,,,,,,,,,,,,,,,,,,,3) Theres good 12 VDC for control getting to the board,,,,,,,,,,,,,,,,,,,,,,,,,,4) The heating element itself is okay and works if power is jumper to it,,,,,,,,,,,,,,,,,,,,,,  SO SINCE 120 VAC IS PRESENT ITS EITHER NOT SENSING IT (board function)  OR ELSE NOT PERFORMING THE AUTO SWITCH FUNCTION (a function of front display panel and/or rear board, see below). Its just hard to believe three rear control boards are all bad.

 There are wires and connectors from the front display panel down to the rear board, so if its possible to get to them I would next concentrate my troubleshooting on that wiring and connections or else consider those display panel issues described below on the web page I cite. Since three boards act the same I'm starting to doubt its a board problem and you have pretty well eliminated the other things I asked about above. It would be nice to have another display panel in case that's the problem  (Yeah right who has one of those laying around lol) LOLer I bought a new one and also a control  button panel and installed them because I was having trouble testing them. I have run continuity checks and diagnostic tests on the harness by having the DW  push the buttons and move a probe passed through the window while I was outside at the lower panel. and found no fault. You just mentioned that it restarts on auto when the connection is broken anyway.

Although this concerns ARP Installation:  https://www.arprv.com/dometic-rm1350.php

I didn't know that they had troubleshooting! I'll do that.  Thanks.

it has some good info regarding troubleshooting and especially list Error Code EO as :      ""No communications between the Dometic control board in the cooling unit compartment and the front display panel. Check for bad wiring connections, power down and back up. Control reverts to full automatic operation.""   If you look at the above web page under DIAGNOSTIC MODE it discusses COMMUNICATION FAILURE but it appears it would revert to full automatic operation BUT YOURS ISNT REVERTING TO FULL AUTOMATIC which shoots all this down grrrrrrrrrrrrrrrrrrrr

Oh well check out the web site Diagnostics it may help or confuse you even more  I may be a bit slow here as I am parked in Key West and there are a ton of things to do this week here. Meanwhile I have the heater jumpered  on and the fridge works that way (as well this model will ever work). I will report back. I really appreciate the advice since I am out of Ideas too.  I still have one new main board up my sleeve bit I don't want to chance wrecking it until I understand the problem. SO much to learn! 

John T   Running out of ideas here  

 

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19 hours ago, Kirk W said:

What make/model is the RV? Sitting can impact some things but I can't think of any reason sitting would account for the problem that you have. It seems that the lower circuit board isn't sensing the 120V, even when we know that it is there. The manual seems to be saying that it should detect power and change from gas even if the voltage applied is less than 100V, so it does appear to point to the board, which is difficult to believe. If you do get another lower board, before you do so check to see if there is one available from Dinosaur Electronics to fit your Refrigerator. I have found them to be superior to the OEM boards, cost less, and they have a better warranty. You can get them through this dealer.

Did you happen to check the upper board per page 21 to be sure that the auto feature is actually turned on? 

I do wish Dino made one for this fridge! Seems like everyone has given up on the RM1350. I did replace both boards up top and checked all if the wiring up there. I di have another board but I don't want to put it in if I blew three others. I have to do more diagnostic. I am in Key West right now and there is lots to do and many friends so I may be a bit slow. I appreciate your suggestions because they confirm the path I took and may  just lead to the Ah Ha moment.

 

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Working on it between activities here in Key West.  Also having to fix basement door that opens by itself and AC that sounds like a jackhammer so not much progress.

 Board is 2 sided AC Neutrals  both in and out are  connected at J6&J7. The actual connection is cone in the relay center left. The actual connection seems to be initiated by connector 4 and three in the 4 wire molex. I can't trace how the signal gets from the 6 wire harness to the 4 wire one to actuate though.  I would need to connect AC and DC to it  to find out more and I don't have the power supplies here to do it safely. The most recent board that I remived had evidence of heating on the C5 capacitor but the other old ones have no visual evidence of a any blown components.

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One problem in troubleshooting the circuit boards is a lack of schematic for them. I know of no source for circuit board schematics. I have often wished that I could find one. 

Am I correct that your refrigerator never automatically selects 120V? That seems to be the reason you don't get electric operation. If you had not replaced the main circuit board, I'd suggest that but, unless something is damaging them it seems very unlikely to be the issue. Let me check to see if I can find someone who works in RV repairs to help you.

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3 hours ago, Kirk W said:

One problem in troubleshooting the circuit boards is a lack of schematic for them. I know of no source for circuit board schematics. I have often wished that I could find one. 

Am I correct that your refrigerator never automatically selects 120V? That seems to be the reason you don't get electric operation. If you had not replaced the main circuit board, I'd suggest that but, unless something is damaging them it seems very unlikely to be the issue. Let me check to see if I can find someone who works in RV repairs to help you.

That is so true! I have been unable to find one myself.  I have replaced the board three times so either the board id not the problem or something blows up the boards. I would love that.  Thanks.

PS No hurry I am in Key west for fantasy Fest till Monday and won't get much done anyway. 😀

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Hi. Sorry to be away for a while but we were in Key West for a festival and I didn't have time or tools to do much. Then I caught a foul nasty cold! Today I got back at it in spite of the cold. I went around the board checking every connection coming off of it to be sure that they went to the right place and that they worked. I also tested the Thermostat just to be sure. All were provably good except for the J3 which goes inside the back of the fridge and powers the fans and 2 heating coils. The fans work. The others could be the door heaters.  They did work. . The other is J 12 which is the ground for a Lamp. When J12 is disconnected the light stays on. It seems like there are several things on the same circuit, each with  it's own ground.  Sloppy engineering but not the problem. I also had the DW stay inside and worked the controls while I  checked the wires where they entered the romex connectors. They did work properly. The pins and sockets all looked good on the connectors also.

 In the end I gave in and swapped out the lower board for a new one I had. There is no change.  It did not fix it.

Tomorrow I will call Dinosaur and Dometic.  Other than that I don't know what to try. I am currently running it on electric when needed by jumping the heaters directly to the AC inputs but that won't work when I am not in 86f weather because the fridge will freeze.

 Interestingly I should mention that that fridge used to work terribly. Never got below 38 and was often in the upper 40's in the day. Opening the door caused a rise of 2-3 degrees which took hours to come back. Since I have run it for 2 weeks straight it has gradually improves to where it is 34 at night and it can keep Ice cream frozen. It recovers quickly when opened.  It was left unused for years.

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1. Have you checked to make sure that your rv is level? Or nearly level..

2.This no-start happens to us when I switch the fridge from gas directly to elect. mode  without stopping at off first.      

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15 hours ago, Kahoona said:

Interestingly I should mention that that fridge used to work terribly. Never got below 38 and was often in the upper 40's in the day. Opening the door caused a rise of 2-3 degrees which took hours to come back. Since I have run it for 2 weeks straight it has gradually improves to where it is 34 at night and it can keep Ice cream frozen. It recovers quickly when opened.  It was left unused for years.

Is the operation you are describing here operating with power directly to the 120V heaters? If so that would mean that it is in a constant cool mode since there is no control function. In a healthy cooling unit the continuous operation mode will usually freeze everything if left overnight. If yours can work in constant cool mode and never freeze the lower part of the refrigerator, I have to suspect that the cooling system has issues, but do not see how that could prevent the automatic shift to 120V. Most RV refrigerators do cool better when using propane because it is typically a significantly better heat source. How old is the subject refrigerator? It is sounding to me like you may have more than one problem.

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2 hours ago, Kirk W said:

Is the operation you are describing here operating with power directly to the 120V heaters? Yes If so that would mean that it is in a constant cool mode since there is no control function. In a healthy cooling unit the continuous operation mode will usually freeze everything if left overnight. That is part of the reason I need to get it running the right way. I agree. If yours can work in constant cool mode and never freeze the lower part of the refrigerator, I have to suspect that the cooling system has issues, but do not see how that could prevent the automatic shift to 120V. Thanks, Agreed.That is what is making me crazy! Some say that letting these sit unused for long enough will cause either a sludge like formation or a chemical combination that might be reversed. Once it was put on direct AC  (on the sunny side of the RV) the overnight cooling improved by nearly a degree a day until it got down to 34f. It may improve more but it it makes it to 34 in a tropical temperature I would be happy if only it would function with the proper controls.  Most RV refrigerators do cool better when using propane because it is typically a significantly better heat source. How old is the subject refrigerator? The RV  a 2008 and it had 23,000mi on it. I knew that there would be problems from sitting too long when we got it  but the price was so attractive that I could spend a couple of months and a few thou on it and still do great. is It is sounding to me like you may have more than one problem. Yes, the fridge  had many problems, mainly with poor install and rubber parts mostly fixed now but the AC not passing through is the one I need to focus on now. It is a RM1350, often considered the worst functioning fridge ever. Since I can get 34f I'm  happy.

 I am absolutely baffled. Everything tests correctly and the heaters are delivering heat to the boilers when connected directly. Somewhere there is one connection or little bit of hardware that is failing in an unusual way and I can't find it. Today I have other things I have to do but I will talk to Dinosaur and Dometic as has been suggested. I will also read the service manual again very carefully looking for hints. Anything that anybody can suggest might be the thing I need to hear so all advice is appreciated greatly.

 

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15 hours ago, Don SC said:

1. Have you checked to make sure that your rv is level? Or nearly level..

2.This no-start happens to us when I switch the fridge from gas directly to elect. mode  without stopping at off first.      

Yes it is level and works on gas.

Interesting. 1he 1350 has soft touch buttons and goes straight to auto when turned on. In the end I may wind up installing a switch to choose elect or gas like yours.

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