SOLVED!-Mysterious black box behind Dometic refer?

[AnEv942]

Dometic RM3663 3 way refridgerator...
Just returned from outing and on the way up (&home) refer wasn't working. Usual aux amp draw of 10-12 not showing on amp gauge. I assumed a relay/bad connection, failed constant duty solenoid or something else that would wait until we got home.
After tearing everything apart- simply found no fault with delivery of 12v power, everything is functioning as its supposed to-??

Doh!..Pulled the wires on the refer 12v heater-its dead. Not working-gosh wonder why power usage didn't show..DA 2 hours later...

So pulling the 12v heater to replace however I note a red wire soldered to the heaters plug on board thats preventing me from removing-traced it up to a small mysterious black box. The red wire enters it and is potted. Out of this box also is a black ground wire fastened to gas nozzle bracket, and a blue wire that disappears in loom. I cut the red wire to remove heater wire and it pulls out other end of blue wire? Its not connected. Ive searched everywhere and can find no mention of this lil box-the part number on the box does not show, nor any Dometic diagram shows it. I'm simply at a loss as to its function or if it even was ever hooked up (other than ground and power to it?, end of the blue wire looks like a clean cut.
Pics below, new heater on order,


So long story short-Only thing I can hope at this point is someone has something similar and can see where (if) the blue wire is connected to, or might have an idea what the lil box might be.

Just another view of mysterious box. Note it sets beside the igniter box, also the unknown blue wire is not the test wire from igniter board plug?

Oh just pic of red wire from mysterious black box that is soldered to heater plug. Unless I can find purpose I'm not reconnecting?

Update SOLVED! See Chris's reply (10th post)

[AnEv942]

DING DING DING!

Wow-where did you find that?Ohhhh
Exactly what I have. I'll be dipped...copied to my cpu.
THANKS! Chris.
Cool, since the factory fan isn't used Ill disconnect completely for the moment-rewire later like it should be as a back up, obviously mine has been hacked.

The thermo disk is 158°-hottest I've measured on a 102 degree day where disk is located is 140° so fan never has come on -and as its currently mis-wired even if disk was lower fan wouldn't come on unless refer was running on 12v heater. Wow-been like this I assume since recall work done several years ago..

At any rate The loose blue wire I was stressing over, as wire coming down behind coils from fan is red must have been spliced behind coils to blue somewhere and I pulled it loose when removing the heater wire. non issue-awesome

Mystery SOLVED! Thanks again Chris

[Chris_Bryant]

That is part of the Dometic fan kit-


It keeps the fan power from going through the board.

[PaulJ2]

I would guess it is a relay to power something else when the element is on. Like you said, maybe a fan,indicator light or something, but apparently not used.

[AnEv942]

Hmm...well seeing the part number listed is encouraging. Switch/relay, interesting. The only thing external that might be switched thats not actually part of refer is the fleetwood added fan, um...but its powered by take off from board. I wonder, if when recall performed the fan source moved due to the recall added 2 power interrupts..

[96Bounder30E]

This rv parts site says it is a switch, relay.........

http://www.rvdealership.com/rvdstore/pb.aspx?type=&PackID=9&ProductID=142433&CategoryID=1&isfull=Fal...

[MrWizard]

"automatic re-ignition" when the flame goes out while driving ? ?

[dougrainer]

When the unit is back and wired, see if the blue wire has 12 volts when the 12 volt element is activated. Doug

[AnEv942]

Thanks. Yes we've owned since new, and no its not part of the recall work which we had done. It could be option (fleetwood) not utilized? as I just cant find where blue wire might have been connected. I'm pretty sure not actually part of refer due to lack of any Dometic documentation anywhere. I find it odd would have been just stuffed in loom open ended if its hot-more puzzled at the soldered on power wire though because it looks like something I might have done, possibly was a separate plug that wouldn't fit on new board when changed out. Cant imagine doing that without looking at what was being powered.

Tomorrow Ill reconnect the red wire to power from 12v heater feed, test blue wire to see if its energized when 12v heater turned on, though that wouldn't explain purpose of the lil potted box and or where blue wire goes or went.

[Reddog1]

Moved from TC Forum.

Wayne
Moderator

[darsben]

Have you owned the unit since new. Dometic had a big recall and a new part had to be installed to prevent gas leakage or some such thing. Make sure the box is not the recall work.
Your model was one that was recalled

http://67.238.126.140/recall.php