Mystery wires on Dometic fridge

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Claude
Posts: 11
Joined: October 20th, 2021, 12:47 pm

Mystery wires on Dometic fridge

Post by Claude »

I have a Dometic RM3663 installed in a 1997 Concourse SE that misbehaved on our last camping trip. The short story is I noticed that the fridge wasn't working in the gas mode (check light was on). The unit would ignite and I could get flame but after 45 seconds, it shut down. The manual mentioned that this happens from time to time, but if you try 3 or 4 times to get it going and it won't, somebody who knows more than me should look it over.

Checking Youtube when I got home, I found that there are some simple things to do before heading to the RV repair shop and at this point, all seems well. And I now have a pretty good understanding of how the gas side of the fridge works. But here's my question:

In doing my diagnostics, I removed the covers from both the igniter and circuit board to check for loose electrical connections. I found 2 wires that were not connected and began to poke around. More often than not that leads to trouble and making an uneducated guess is not a good diagnostic technique. Thankfully, the only thing I fried on the Dragon board was the 5 amp fuse. But I'm still perplexed about these wires. Specifically, I'm talking about the red one in front of the board, and the blue one that comes out of the upper right of the board. Neither of them seem to have a home.
fridge wires.jpg
It seems goofy to me that these wires are "free floating" or left overs. Does anyone have an idea where they attach or if indeed they are meant to be unused? I can take more photos if that would be helpful. Thanks all for your help.
1997 Concourse SE Ford Triton 6.8L V-10
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caconcourse
Posts: 489
Joined: October 31st, 2014, 10:25 pm

Re: Mystery wires on Dometic fridge

Post by caconcourse »

Here are a couple of pictures of my installed working Dino circuit card. It looks like the big red wire is the DC igniter wire in J1 (for running the fridge in DC mode) which is accompanied by the 30amp fuse above it. Since DC barely works, it could be the previous owner disconnected it effectively disabling that mode. The blue wire in mine is connecting to something but it is off the to the right of the picture (part of igniter/valve connector).
DinoBoard (1).jpg
DinoBoard (1).jpg
Attachments
DinoBoard (2).jpg
Clay
2001 Concourse
Santa Barbara, CA
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caconcourse
Posts: 489
Joined: October 31st, 2014, 10:25 pm

Re: Mystery wires on Dometic fridge

Post by caconcourse »

Sorry for the duplicated picture above. As an added note, my refrigerator had the check light problem when I first got it, but that was fixed when I installed the Dinosaur card. The problem had to do with a weak ground on the original Dometic card, and there should be a second ground jumper added to the Dinosaur card between J10 and a ground point, as shown in the picture.

UPDATE: I went out and checked the blue wire, and it is indeed not attached to anything, so that is apparently normal. There may be some kind of sensor attached (thermistor perhaps), but it has shrink tube covering the end.
Clay
2001 Concourse
Santa Barbara, CA
Claude
Posts: 11
Joined: October 20th, 2021, 12:47 pm

Re: Mystery wires on Dometic fridge

Post by Claude »

Thank you, thank you, thank you! My system had the 30 amp fuse removed and your guess that a previous owner did something is spot on! That explains why the DC never worked. I'll get "under the hood" and see if I need any more help. J1. Why didn't I think of that? :) You, my friend, are a life saver.
1997 Concourse SE Ford Triton 6.8L V-10
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