Refer will run on propane, but not on AC

[MTM Time]

Hello All,

I have what seems to be a common problem with my Dometic DM-2652 refrigerator. I recently discovered it will only run on propane. I watched a dozen or so YouTube vids and weeded through many of the posts on this forum, but have yet to come up with a definitive answer.

I have performed some trouble shooting with my multi meter and this is what I have discovered so far:

My eyebrow control board is functioning correctly.
I have 120 VAC at the plug behind the refer.
I have 120 VAC at the terminal where the plug connects to the board.
In the attached picture, you will see two fuses. The 5amp fuse on the right is the AC heater fuse according to my manual. The yellow circled fuse is the 3amp Control System fuse.
I have 120 VAC at both ends of the 5amp.
I do not have 120 VAC at either end of the 3amp, and a continuity test reveals the 3amp fuse is good.

My gut is telling me the board is bad, but I would be open to and appreciate additional troubleshooting tips if you think that all is not lost yet...

However, if I do need a new board, does anyone here have any experience with these Dinosaur Electric products out of Oregon? I have been reading that they might be better than OEM in terms of replacement.

Thank you all in advance.

[rhagfo]

The circled 3 amp fuse is 12 volt DC for the control board. I would disconnect the 120 to the electric element and test for resistance, not sure of the value, not an open.

[mikec557]

Originally Posted by MTM Time

Hello All,

I have what seems to be a common problem with my Dometic DM-2652 refrigerator. I recently discovered it will only run on propane. I watched a dozen or so YouTube vids and weeded through many of the posts on this forum, but have yet to come up with a definitive answer.

I have performed some trouble shooting with my multi meter and this is what I have discovered so far:

My eyebrow control board is functioning correctly.
I have 120 VAC at the plug behind the refer.
I have 120 VAC at the terminal where the plug connects to the board.
In the attached picture, you will see two fuses. The 5amp fuse on the right is the AC heater fuse according to my manual. The yellow circled fuse is the 3amp Control System fuse.
I have 120 VAC at both ends of the 5amp.
I do not have 120 VAC at either end of the 3amp, and a continuity test reveals the 3amp fuse is good.

My gut is telling me the board is bad, but I would be open to and appreciate additional troubleshooting tips if you think that all is not lost yet...

However, if I do need a new board, does anyone here have any experience with these Dinosaur Electric products out of Oregon? I have been reading that they might be better than OEM in terms of replacement.

Thank you all in advance.

I'm not much help on the troubleshooting. When our fridge board went bad, both 120vac and propane didn't work. The fridge would just go dead. We'd discover that some time after the fridge shut off. I'd push the on button on the eyebrow and it would run again for a couple days. Mobile RV tech said it was probably a defect in the board that was related to overheating. Get hot, short out. Cool down, make connection again. Dometic covered under warranty, but it took close to 15 days from first call to getting the replacement board.

That board was still working when we sold the RV. But later that same year, the circuit board went bad on our Dometic water heater. Two defective Dometic circuit boards in a year. I didn't have the patience, nor did we want to go without hot water, for 15 days.. I bought the Dinosaur Electric replacement board for the water heater, from Amazon. It worked great.

I know you're working on the fridge instead of a water heater. But I would trust and buy the right Dinosaur board rather than another Dometic board.

[FlyingAroundRV]

The Dinosaur boards are a drop-in replacement for the OEM boards and are reputed to be a better quality. I bought one when I thought my controller board was bad. There is a slight difference in the mounting and the earthing screw method is slightly different but doesn't pose any problems for replacement.

WRT to troubleshooting.
1) unplug the fridge from the powerpoing at the back of the fridge (near the controller board) and plug in an appliance that draws a significant amount of power such as a toaster or a hair dryer. If the appliance runs OK the the ac power to the controller is OK. In my situation, measuring the ac at the powerpoint showed the correct voltage under no-load condition but the wiring to that powerpoint in the power distribution box was dodgy and wouldn't support the current that the fridge heating element draws.
2) Where the 12V connects to the controller board, it first travels through a thermal cutout. Thsi device is a short cylindrical object attached to the side of the heater chimney. This chimney has the electrical heating element inside and also has the gas flame at the bottom. This cutout senses the temperature of the chimney and if it gets too hot it shuts the 12V off to the controller, effectively turning the fridge off. Test this as follows: trace the two wires from the thermal cutoff back to the controller. With the ac plug disconnected from the powerpoint, remove one of the cutoff wires from the controller board so that you can do a resistance measurement of it. It should measure very low resistance, in the order of just a few ohms.
3) Still with the ac disconnected, unplug the wires that go to the heating element in the heating chimney. Measure the resistance of the heater element. It should be around 40 ohms. If it reads very high resistance or open circuit then the heater elemnt is bad. You can replace the heater element. They aren't expensive, but they are fiddly to get out and put back in.
4) If the ac to the controller board is OK and the thermal cutout is OK and the heater element reads the correct ohms and the two fuses on the board are OK (you can get an ohms reading on them when you take them out of the board) then it is possible that the controller board is bad. You can test this if you can find someone with a similar unit who will let you swap out the board temporarily. However, these boards are very simple devices and are pretty robust so don't fail as often as the heater elements.

HTH.

[MTM Time]

Thanks to all the responded and provided advice and trouble shooting tips.
Those are getting saved for future reference to be sure.

Craziest thing happened... I went out the next morning to start trouble the trouble shooting process. I was going to start by testing the refer outlet with a hair dryer, then move on to testing the AC heater element for resistance, and so on...

I unplugged the refer from the outlet and heard a "CLICK" that I hadn't heard previously when unplugging the refer, subsequently I heard the gas ignitor ticking away as it went through its start up process (propane was off however).

Something about that initial "CLICK" told me to check the inside of the refer.
I plugged the refer back in and went inside to check the refer temp, and sure enough, it was fully functioning on AC. As cold as it has ever been.

Not sure what gremlins I am dealing with or if the bit of troubleshooting I had performed previously gave the system the "nudge" it needed to wake up, or what. Or, perhaps my issue is intermittent. Whatever the case, the refer is working on AC for the time being and fingers crossed it stays that way for a good long while.

Thanks again to all who responded so quickly, I hope I can return the favor one day.

-MTM Time

[ChuckS]

Glad the fridge is now working on 120 volt AC mode.. Id still check the heaters by unplugging them and verifying proper resistance reading..

Id also take a long look at the overtemp reset switch on the flue stack ...

Link for Dometic 2652 troubleshooting PDF in case you dont have

https://rvrefrigeratorrepair.com/wp-...ice-RM2612.pdf

This link tells you what the ohms reading should be for the heaters

[MTM Time]

Outstanding, thank you Chuck!