Dometic Fridge Won't Run on AC

I"m no repairman but I'd probably start at the electric heater and work back to where the electrical power is lost. If you find electric power at the heater then that's probably the problem. I'm usually not that lucky.

you still need a 12volt source ,put a good battery in and try again.

Check the heating element for power there.

It will be located about where the propane burner is, attached to one of the tubes, above the burner. You should see two wires going to it.
Put a test meter on the contacts, or wires attached to the element. You may have to probe the insulation on the wires. BE CAREFUL!! Don't zap yourself! Or turn the power off and make connection with the test meter and then turn power back on.

If you have 110 volts there, then the element is burned out and needs to be replaced.

If no 110 volts there, trace the circuit back to connectors and check each side of the connectors for power.

If you have power on one side but not the other, the connector joint is bad.

Also, check the obvious - any fuses that may be there, and also make sure you have shore power supplying the breaker that supplies the fridge.

If his control panel inside the rig is lit, then he's got 12v, probably from the power converter when he's on AC.

Even when AC is present at the fridge, I believe it's possible to tell the fridge to NOT switch to AC at the control panel inside, even when AC power is supplied. You can force it to stay on propane. Make sure this is not the case. Depress the button that manually switches from propane to AC.

I have a P-711 board. Make sure that your J7 and J8 connections are sound on the board. If you have the knowledge, you can trace these to the AC heating element and see if power is going to it all along it's path.

You might also have a thermal cutoff fuse that was part of a recall on a number of Dometic fridges in the early 2000s; maybe earlier or later, I dont know. But this fuse is usually located against the back wall of the outside fridge compartment. It is a piece of metal that has two screws into the back wall. This piece of metal has some "fingers" that hold the thermal cutoff fuse within some insulation. You will see wires running through the "fingers".

Test for continuity through this fuse by either testing at the ends of the wires (can remember where they terminate) or by exposing the fuse and testing it individually. There should be continuity through it.

I always assumed that if the T-cutoff fuse is blown, the fridge would not work on propane, either, but who knows? Not me.

You can also trace the wires leading to the AC heating element that is inside the chimney/flue, whatever it is called.

I'm no repairman, either. Just some things I learned while installing my Dinosaur board.

Ragingbull wrote:
I replaced my board several yrs ago with a Dinosaur P-711 due to a propane igniter issue. My son moved into it for about 6 months. As he's out now I'm going through the camper and found that the fridge won't start on AC. When you turn it on, the lights for DC and gas illuminate and it works on them. It won"t try to switch to AC. I checked all the fuses, verified the outlet is working, and checked for loose wiring. Any other things I should check into?

I just finished fixing mine,would not work on AC, gas OK, had a open heater element. Did a write up, photos and video of the job for reference. The fridge is a Dometic DM2652.

Ray

P-711 board
p711 install instruction

If you have the added recall update, its working. Just to clarify-The recall, other than adding the sheet metal containment, added the mentioned thermal fused link and disk to flue. Its on the 12v feed to refer. In the event of a fire or abnormally high temps either safty link would cut 12v feed to refer-effectivly shuts down refer- irregardless of mode its in, wether in 12v,110v or gas.

Though eyebrows or control panels can & do go bad-not often. Id also suspect heater if ALL fuses are good.
All of the 110v heaters I've seen the wires are sealed at the heater side, run directly to board J7 & J8 teminals. Id test at the board for power J5 & J6 verfying 110 input, output to heater j7 J8. If power, unplug 110v cord to refer (sticking meter leads in board ok but not fingers), then unplug the 110v heater leads. Test leads from heater for continuity/resistance- bout 44+/- ohms. You need a multi meter. If no power at J7 & J8 double check the 5amp fuse

Thanks everyone. I pretty much eliminated everything but the element. I need to borrow a multimeter from work to check it. Nice write up. I looked up the exploded drawing on Dometic's website so will probably end up doing this too.

A bad element will not keep it from trying to run on A.C. power, it just won't cool.
Did you actually measure the voltage across the fuse on the board? These fuses fail quite often by building up a bit of heat, and the element comes un-soldered from the end caps, so the fuse looks good, but doesn't conduct power.

My Dometic with a P-711 board did the same thing a couple weeks ago. I couldn't get it to switch to AC at all. It turned out to be the 10A fuse on the Dinosaur P-711 board.

Markh12 wrote:
My Dometic with a P-711 board did the same thing a couple weeks ago. I couldn't get it to switch to AC at all. It turned out to be the 10A fuse on the Dinosaur P-711 board.

That was it! Finally got a chance to mess with it today. Thanks for all the responses.