Dometic fridge 12v power problem.

Submitted: Wednesday, Feb 23, 2011 at 20:36

ThreadID: 84568 Views:9836 Replies:5 FollowUps:6

This Thread has been Archived

Member - Toyocrusa (NSW)

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.

Back Expand Un-Read 0 Moderator Share

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

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

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

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

Thursday, Feb 24, 2011 at 13:10

Hi,
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.
Guy

AnswerID: 446436

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

Thursday, Feb 24, 2011 at 15:39

Hi
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

Peter

FollowupID: 718831

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

Thursday, Feb 24, 2011 at 15:49

Hi
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

Peter

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