Dometic fridge 12v power problem.

Submitted: Wednesday, Feb 23, 2011 at 20:36
ThreadID: 84568 Views:8696 Replies:5 FollowUps:6
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G'day all. I have a Jayco 2010 Sterling with a Dometic RM 2553 Three way fridge. It will work on 240v but not on 12v. The van has a Setec ST35-11 regulator. It has a terminal marked Aux In + VE which I'm sure is the power supply from the vehicle. With vehicle connected and running there is 13.97v at this terminal. There is 2.07v with vehicle off (not sure why, I thought it should be 0v) The on board battery has 14.39v with solar connected and in daylight. All terminals on the setec marked Batt + VE and L1 to L5 have 14.39V
The fridge is switched to 12vdc but at the rear of it there is a terminal block marked 12v DC Heater + and - (accessed by taking off the outside grille) which does not have any voltage. There is a larger terminal box beside the block but it is not accessible from the grille hole. Before I slide the fridge out would anyone have any more ideas on testing components. Thanks, Bob.

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Reply By: oldtrack123 - Wednesday, Feb 23, 2011 at 21:38

Wednesday, Feb 23, 2011 at 21:38
Hi Toyocrusa

That block is the 12v supply to the fridge.
No point in pulling the fridge out if you do not have voltage there.
Is the van still under warranty ?,if so suggest you take it to dealer to sort out

Are there incoming wires attached to the terminals?
The fridge should be wired so that engine must be running to get voltage @ those teminals ,is this how you have tested?

It should not be supplied from the Setec or house battery.
Is your vehicle wired for a separate supply to the fridge via an ignition controlled relay as recommended.?

Have you checked for a blown fuse [20amp] in the fridge feed line?

AnswerID: 446399

Follow Up By: Member - Toyocrusa (NSW) - Thursday, Feb 24, 2011 at 06:45

Thursday, Feb 24, 2011 at 06:45
Hi Peter. Vehicle has a 12pin plug and is wired up through a relay operated from the ign switch so will only supply power with vehicle running (or ign on). It appears that the supply wire from the 12pin plug runs up to the Setec but I will double check that on the weekend. I have a 20amp fuse on the car feedline which is OK so looked for a fuse on the feed line in the van but could not find one, hence I thought it may be on the fridge body somewhere. Closest dealer is over an hour away so I may have to end up taking it to them if I can't sort it out. Just wanted to make sure it wasn't something simple first. Thanks for your help. Bob

FollowupID: 718796

Reply By: Roughasguts - Wednesday, Feb 23, 2011 at 22:41

Wednesday, Feb 23, 2011 at 22:41
There is a Orange wire from your 7pin plug that should go to the 12 volt heating element on your fridge. But that won't work unless your car is also providing 12 volts to that orange wire.

Also when your have sorted the problem, the fridge will drain your car battery in no time flat unless the engine is running.

AnswerID: 446407

Follow Up By: Member - Toyocrusa (NSW) - Thursday, Feb 24, 2011 at 06:51

Thursday, Feb 24, 2011 at 06:51
Thanks RG, checking it out further on the weekend. Bob

FollowupID: 718798

Reply By: Nomadic Navara - Thursday, Feb 24, 2011 at 00:20

Thursday, Feb 24, 2011 at 00:20
What style plug do you have on your van? Is it the 12 pin type that is normally fitted to Jaycos? These have separate cables for the fridge and house supply. If you have a 7 pin plug then may be who ever replaced the original plug with that one did not connect the fridge wire.

See Site Link for connection details.

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AnswerID: 446412

Follow Up By: Member - Toyocrusa (NSW) - Thursday, Feb 24, 2011 at 06:50

Thursday, Feb 24, 2011 at 06:50
Hi Peter. I have placed a more detailed reply to the first poster.Just trying to get some more info before investigating further on the weekend. Your sitelink is a big help. Thanks again. Regards,Bob

FollowupID: 718797

Reply By: guy007 - Thursday, Feb 24, 2011 at 13:10

Thursday, Feb 24, 2011 at 13:10
My 2008 Jayco Discovery has the same fridge. Behind the lower vent is a fridge motion switch which automatically supplies 12v from the vehicle when you start moving and turns it off when you stop.Check if you have this switch.
My Jayco had a pitiful thin wire from the fridge switch to the 7 pin plug so I rewired it to a 12 pin plug and used one of the heavier terminals. No need for a relay in the vehicle as the fridge motion switch takes care of your battery.
Hope this helps.
AnswerID: 446436

Follow Up By: oldtrack123 - Thursday, Feb 24, 2011 at 15:39

Thursday, Feb 24, 2011 at 15:39
Guy has a valid point , perhaps that is how your fridge is wired[with a motion switch to isolate fridge from the house battery unless in motion.

However you still need an battery isolator ] ignition controlled or voltage controlled relay vehicle & van battery.

As PeterD pointed out for best 12v performance the fridge should have it's own seperate feed from the positive out terminal of the battery your ignition controlled relay.
This should be a separate feed to the van battery supply . If this is correct you will have 12v @ both pin 8 [orange] &12 [voilet] of your 12pin plug & socket

The wires to these pins,from both directions, should be quite heavy
[COPPER dia of at least 4mm] depending on how far the cables run from fridge & van battery to the vehicle battery

FollowupID: 718831

Follow Up By: oldtrack123 - Thursday, Feb 24, 2011 at 15:49

Thursday, Feb 24, 2011 at 15:49
I cannot edit so a CORRECTION & addition TO ABOVE.

SHOULD READ "from the positive out terminal of your ignition controlled relay[ battery isolator ?]"

If your van has a motion switch for fridge you will not flatten either battery.

If no motion switch,you will still require a second igniition contolled relay in the fridge feed from the battery isolator

FollowupID: 718835

Follow Up By: Member - Toyocrusa (NSW) - Thursday, Feb 24, 2011 at 20:41

Thursday, Feb 24, 2011 at 20:41
Guy. The motion switch is something I wasn't aware of so will look for that on the weekend. Thanks for the tip.
Peter. The fridge power source is from the vehicle only. Definately not from the house battery. I also have the 12v wire to charge the onboard battery. Both power supplies are through the correct pin no,s and have 4mm wire with the fridge supply through an ignition switched relay in the vehicle. The earth return is also 4mm and runs back to the vehicle battery earth. 4mm is the largest wire you can fit into the 12pin terminals. The van wires all seem to be white in the van body so I will just have to trace carefully when I check over the weekend. Thanks for your help. Bob.

FollowupID: 718856

Reply By: Member - Joel and Michelle (WA - Thursday, Feb 24, 2011 at 15:47

Thursday, Feb 24, 2011 at 15:47
G'day Toyocruiser
I have a 2008 Jayco Sterling with the same fridge.I have an Anderson plug wired from the vehicle and this is solely for the fridge. It does nothing else as the fridge is quite a high power draw, a bit too much for the tiny wires of the seven pin plug.
It may not be the same?...
Good luck
AnswerID: 446450

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