Dometic fridge won't run on 12v DC.

[JCamper]

Need help diagnosing my model DM2652RBX 3 way fridge. It will no longer run on the TV 12v as it used to. It tries to light as though the gas mode is selected (which its not) and should then click over to the 12v. The element is fine because it all runs fine when we have full hook ups. I've checked the 2 fuses behind the box and they're fine. Meyer reads 13-14v DC when connected to the TV. So is there another fuse somewhere that I can't see? Something else I'm missing?


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[prof_fate]

if I think you're saying what I think your saying..i'm having the same problem.

Assuming you have gas, line is bled, you turn on the fridge without shore power and it should click (the igniter) and light the propane which runs the fridge. (on shore power there is an electrical heating element that runs).

I replaced my ignitor and no go - would not light. I can light it manually (requires pulling a few tin guards to get to the burner) and as long as it's on, it runs. But it won't 'self ignite'.

I've not been able to get an answer to my issue - if your's is the same maybe together we can find it.

[bubbles]

The OP says it is a 3 way fridge (ac/dc/gas) and it's the dc (12 volt) portion that isn't working. I didn't know these types were still in existence. Anyway, if I'm correct not the same issue as yours.

[prof_fate]

can I assume it works on the same principal - so the 12v heats an element that runs the fridge.

So if you have 12v at the element and no heat there, then you need to disconnect the element and check the resistance. if it's zero (no resistance) then the element is broken/burned out and needs replaced. Yoy'll need to find the spec for how much resistance there should be in a good element.

This may help
http://www.fourwh.com/NewDometicRefrigeratorManual.pdf

[Mr Havercamp]

Originally Posted by JCamper

The element is fine because it all runs fine when we have full hook ups. I've checked the 2 fuses behind the box and they're fine. Meyer reads 13-14v DC when connected to the TV. So is there another fuse somewhere that I can't see? Something else I'm missing?


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A 3 way has 2 electric elements, one for AC mode and one for DC.

[prof_fate]

from my link above - |
note:
the
dc mode is a holding mode not a full cool
-
ing mode.
dc should be used once the unit is cooled
down and constant supply of
dc available (driving
down the road).

[Bama Rambler]

A DM2652 is only a 2-way fridge, not a 3-way. At least according to all the service and owners manuals I can find.

However, If the element is good and the relay is engaging, there's a 30 amp inline fuse between the 12v+ and terminal 30 on the relay. I'd check that fuse to be sure it's good.

[bikendan]

Never heard of any PT product with a 3 way fridge.
Those are normally only in folding trailers and truck campers.

[JCamper]

This particular model seems to not be available when you look on the Dometic site. It is a 3 way because we've had the trailer for 4 years now and know it has the 12v DC. It's worked until now.
The heating element has 120ac And 12v DC listed on it.
I'm not sure how it uses the same one. What I can't find is a blade fuse, or any fuse for that matter related to the 12v DC. I see a 3 and a 5 amp bus fuse but both have AC listed above them.

Anyone m ow where the fuse might be? It's also NOT in the main breaker in the trailer.

[rbq]

Most RV fridges are AC or propane. They use the 12 volt for the controls & to fire the ignitor for the propane & that's as far at the 12 volt go, so if you're trying to make it work with just 12 volt it's not going to happen. Make sure the propane it turned on & the lines are bled from any air that entered when connecting & it should run unless there are other problems. Does the fridge work on shore power?

[Grampa Jim]

Jcamper.....when it tries to light,,,,,does it might momentarily and then shut off. If so,,,,,your flame sensor is sooted over and needs to be cleaned off.

[Bama Rambler]

Can you post a pic of the control board and the heating element?

If it uses the same conductors for both 120 and 12 volts then if it's about 350 watts on 120 volts it would be about 3 watts on 12 volts.

It could be a dual element heater with two different heating elements in one tube, but it would have at least 3 terminals for that.

[rvdoctor]

A 3 way fridge will have 3 glass type fuses in the circuit board the first being a 35 amp glass type fuse. Must remove the black lower circuit board cover to gain access. Check the 35 amp fuse as it controls the heating element. Check all grounds very important. Make sure grounds are clean and tight. OHMs for element is model 2354=.92, models 2454/2554=.80, and model 2663=.67. Check voltages at eye brow panel and at circuit board. Possible malfunctions are eye brow, circuit board, element, or harness assembly from eye brow to circuit board. Service manual part number is 3311143.000. Never heard of a 3 way DM2652 fridge. Only Americana models with 3 way are RM 2354,2454,2554, and 2663.

[pdqparalegal1]

Originally Posted by bikendan

Never heard of any PT product with a 3 way fridge.
Those are normally only in folding trailers and truck campers.

1978 Winnebago 3 way, best cool was gas.

[2015 Flagstaff 21DS]

Infinite resistance is open. Zero resistance is dead short. But I'm sure you know that.

[rockfordroo]

Maybe this will help?

[JCamper]

Hi Bama...
So here are the pics. I tried to show the flu with the 110AC and 12V DC as well as the circuit board and fuses (all which have full continuity by the way.)
Also I checked resistance on the heating element and get 42 ohms? at least that's what the meter read.

For the life of me I can't find any DC fuse. The 2 fuses in the pics are labled AC.
I know I'm going nuts in this life, but this fridge up until this last trip would work on the 12v from the TV while going down the road.
The Ol Lady's job was to make sure to change the fridge over any time we stopped and turned the truck off. We'd have to switch to LP.

I've checked the plug and truck connections and they show 14v while TV is running.


By the way this is a Dometic DM2652RBX model

[Bama Rambler]

Can you take a pic of the front panel in the different modes? I'd like to see what, if any lights are on in the different modes.

[JCamper]

So we were told and have been doing as such...
You hook to TV and switch off of gas and the fridge detects the power source AC or DC and works based on which is available.
The Auto light comes on and unless there is a problem the Check light will stay off.


When we follow this procedure the Check light stays off until we start going down the road. Usually the first time we have to make a pit stop I'll look in and both the Auto and Check light will be on indicating that there was a problem.


Sometimes we'll wait and no check light for 20-25 mins before we depart.

[RJHuser]

HM - Interesting.

Just looked on Dometic's website, and the DM2652RBX is listed as a two-way only, not three-way.

Looking at the picture of the panel you posted, it's not a three-way, no indicator lights for 12 volt as normally used on three-way units.

Are you sure of the model number?

Rick