Problems getting a 3way fridge to work on 12v DC

greyway1

New Member
Aug 28, 2019
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New Zealand
Hi, I have a Dometic 3way fridge freezer that works fine on 240v & gas, but will not work on 12v, it is auto select but will not select 12v when 240v is disconnected
 

Drover

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Nov 7, 2013
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Have a look at the back down the bottom the plastic box housing the circuit board should have a small wire coming from the D+ terminal, it may even have a tag on the wire, with van connected to the tug 12v it should be live if not then you have a break somewhere... this wire activates the relay to let 12v power the fridge.... The fridge shouldn't work off the van battery at all.
 
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greyway1

New Member
Aug 28, 2019
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New Zealand
Thanks for your reply, my 5th wheel has never had the 12v connected so there are no wires connected to the D+ wire out from circuit board or any input from tow vehicle. I have only tried to power up using a battery outside with connections to D+ and other terminal block
 

Drover

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Nov 7, 2013
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Well if connect the battery to the Pos and Neg terminal block and hook the D+ to the pos it should see the 12v BUT the battery needs to be up around the 12.7v at least if I recall, but really if it works on gas and 240, 12v will only keep it at temp while driving it wont do much else other than draw a heap of power....