Dometic Refrigerator E3 code

Disconect 12v power to the board to reset

You are confusing having 120 volts with refer operation. ALL 120 volts does for the refer is power the 120 element when on 120. So, you connected to 220 volts. THAT usually blows the 120 element FUSE on the Refer control board and sometimes burns out the 120 element. It takes just 12 volts to operate the refer controls. You have that since the refer powers up. The ONLY reset button is on the outside burner flue cover and IF that button trips, you will have NO power to the refer at all to power the refer controls. Check the fuses on the rear refer control board. Rarely does a 220 hit destroy the Refer board on a Dometic. Doug

So I’ve disconnected 120v AC power to the trailer and have only 12v power feeding the trailer. I tried disconnecting 12v power for a few minutes but as soon as I restore 12v power I immediately get the E3 error code. I only know of two fuses on the 12v side. One inline 4 amp and one mini 5 amp in the circuit board. Both fuses test good. I know I have 12 volts feeding the control board, I know the fuses are good, but still get the E3 code. I don’t see any type of reset button and since I have the display reading E3 and 12v power to the circuit board, I don’t think a reset button, (if there was one) is my problem. Unless someone can steer me in another direction, or tell me something different to check, I think my next move is to spend the $200 and buy a new circuit board. Thanks for the suggestions and if anyone has any more, I surely welcome them.

Did you check the GLASS fuse on the board? That is the 120 element fuse.
It is 5 amp. I have never seen the E3 code but the manual states cooling unit problem which is a catch all for any problem causing lack of cooling. There is nothing on a Dometic that could tell you, you have a bad cooling unit. Doug

PS did you try this?

To preform a diagnostics test:
1) Turn off the refrigerator with the ON/OFF button.
2) Press and hold the TEMP.SET button, then press the ON/OFF button.
3) Release the TEMP.SET button. Each subsequent press or the TEMP.SET button will toggle through the list of functions in the table below:

I’d still find the hi limit reset switch located on the stack for the burner and electric heating element and press it to reset the hi limit switch

ChuckSteed wrote:
I’d still find the hi limit reset switch located on the stack for the burner and electric heating element and press it to reset the hi limit switch

If the Hi limit switch is tripped, you will NOT have power to the refer and controls. The OP does have power to his eyebrow board. Doug

Yesterday afternoon I pulled out my Fluke multi meter and started testing everything I could find in the service manual. The 120v elements ohm reading was in spec as well as the thermistor. All of the fuses were good and I have good 12v power feeding the circuit board. The odd things I discovered were....I would test the 5amp 12v fuse and have 12.8 volts. 30 minutes later I would check it and have no power. Check it again an hour later and have power. When I open the fridge door the light would come on and then randomly go off. I would shut the power off and then the light would work again, but then go out again. Sometimes the light would stay on for only a few seconds and sometimes it would stay on for about 30 to 45 seconds. Anyway, it appears that there is a lot of random things going on so I ordered a new circuit board and I’ll go from there. Oh, I also pulled the old circuit board and I cant see anything visable that is burnt, but I’ve ran out of things to test so I’m going to replace it and see where it gets me. Thanks for all the suggestions. I’ll report the end result when I’m finished. Maybe it will help someone else someday.

mxdad777 wrote:
Yesterday afternoon I pulled out my Fluke multi meter and started testing everything I could find in the service manual. The 120v elements ohm reading was in spec as well as the thermistor. All of the fuses were good and I have good 12v power feeding the circuit board. The odd things I discovered were....I would test the 5amp 12v fuse and have 12.8 volts. 30 minutes later I would check it and have no power. Check it again an hour later and have power. When I open the fridge door the light would come on and then randomly go off. I would shut the power off and then the light would work again, but then go out again. Sometimes the light would stay on for only a few seconds and sometimes it would stay on for about 30 to 45 seconds. Anyway, it appears that there is a lot of random things going on so I ordered a new circuit board and I’ll go from there. Oh, I also pulled the old circuit board and I cant see anything visable that is burnt, but I’ve ran out of things to test so I’m going to replace it and see where it gets me. Thanks for all the suggestions. I’ll report the end result when I’m finished. Maybe it will help someone else someday.

It's possible that your converter put out an excessively high voltage for a brief moment when it fried and that could have taken out the fridge board.

Make sure any hardwired LP/CO detectors you may have are still working or maybe just replace them to be safe.

So I received my new control board today and installed it. After connecting to both 12v and 120v power I turned the fridge on. Immediately the E3 error code came on.:M The only positive news was the interior light stayed on as it is supposed to. It wasn't intermittent like before, but my main problem was still there. My fridge won't work! I once again went back through the service manual and started going over everything again. I went through the trouble shooting codes (turn off, hold the TEMP.SET button down, turn on fridge, scroll through codes) In doing this (don't ask why I didn't try this before) I saw an E1 code pop up. (Hardware fault in gas operation, check controls for DC power, etc) So I go out to the fridge and start checking all of this again. On the flu itself, there is a red and yellow wire attached. I try and remove them to see if there is power there (I'm not even sure what there purpose is) and while trying to remove the wires I see a tiny little black button in between the wires. (see pic below) I remember a few different people on here telling me about a reset button located on the flu, and I looked for one, but never found what to me looked like a reset button. That coupled with the fact that no where in the owners or service manual does it mention anything about a reset button, I had determined that my fridge didn't have one. Well, it does! I pushed that little black button in, went back inside and the fridge started right up and is running like a champ. Now I don't know (and don't really care at this point) if my circuit board was bad or not, but the fact that the light was wigging out before I changed it and now its not, I'm going to say that there was something not quite right with the circuit board. Anyway, I wanted to post this follow up with the hope that maybe it will help someone in the future. As for me, I learned a lot about RV 30amp outlets vs 50amp outlets. I also learned a lot about my refrigerator. Thanks again for everyone's help and input.

dougrainer wrote:

ChuckSteed wrote:
I’d still find the hi limit reset switch located on the stack for the burner and electric heating element and press it to reset the hi limit switch

If the Hi limit switch is tripped, you will NOT have power to the refer and controls. The OP does have power to his eyebrow board. Doug

So apparently this wasn’t the case with the OP’s fridge as he got an E3 code with that reset tripped.