Dometic Caravan 3way Fridge Fault

Most likely element though if a AES model may not be.

Also worth checking to see if a movement activated switch is fitted as it maybe faulty.

Hi,
Sorry should have included Model#,It's a Dometic 175lt 3way Absorption Fridge RM7851. The Fridge is not cooling when running on 12v or connected to the tow vehicle. Works fine on Gas and 240vt.
Cheers Steve

Hi
That makes it a MES [manual energy select] model
The first thing to do is check that you have 12V AT the fridge terminals when it should be running
Then we can take it from there.

PeterQ

Hi Peter,
First of all thank you very much for your help. I checked the power supply at the Fridge. It has two 12v connections One is a12vDC Heating Element the other is 12vDC Electronic.There is no Power at either connection. Both lots of wires come out of a 12v 30amp Relay that has a built in Fuse. Checked Fuse OK. Fridge was in running mode when Checked.
Cheers Steve

HI Steve
Yours being a MES [manual energy source ]selection the electronic 12V is for the gas ignitor /reignitor
That should be from the van battery with small dia cables but fused[5A] as close as possible to the van battery/

THe heating element should not be connected to the van battery but supplied by it's own seperate heavy cables from the vehicle battery
fused again at the vehicle battery[20A]
that feed should also have some automatic means of disconnecting the fridge from the vehicle battery when the engine is not running.
That last can be done by :
[a] an ignition conrtolled realy in the vehicle
[b] a"Fridge Switch in the van which is actually a motion sensor Which detects when the van is not in motion & then after a short time delay switches off
[[c]a voltage sensitive realy which detects the voltage available & will only connect the fridge when the voltage is over 12.7V approx.

To complicate matters many van makers DO NOT wire correctly & have both feeds connected to the van battery
i
THat will lead to the van battery never being fully charged while driving'
You would need to trace back the wiring of BOTH circuits & see when you can pick up 12V
note TESTING with a digital volt meter can be misleading
They will detect voltages that cannot support any real current flow
Best done with a 12V test lamp & judge voltage by brightness, a stop light bulb is a good size

PeterQ

I have just downloaded the manual for the RM7851. It shows three separate 12 V inputs. There is the heavy cable from the tug. There is a second light duty one from the vans house battery and the third one is the D+ wire. Quote from the handbook:

I have not copied the solar instructions (S+)

From your description of power coming from a relay it looks like the fridge was not wired correctly.

Hi All,
Thanks everyone for your help. I have done everything that you have suggested and still not working. I know I'm out of my league with this one,time to call the fridge Doctor and Pay up. Thanks again all and safe travels.
Cheers Steve

Hi PeterD
Those multi model manuals are confusing sometimes
I think if you recheck you will find the 7851 is a MES not an AES model

BUT it does have electronic ignition from the house battery

PeterQ