Another Dometic Fridge not working on 12volts

[Lost in time 1955]

I realise that there have been many posts on this subject after trolling the web, some of it I get, most of it I don't.
Any help appreciated.....

So, I have 14.4 volts coming from pin 10 through the caravan wiring harness. The Fridge/Freezer works very well on gas and on 240volts.
But not alas on 12volts. Fuses all all good.

I have taken some readings from the electical contacts I can access and seem to only have 10.3volts coming out of the relay. My understanding of relays is that they
either work or they dont. 10.3 volts seems odd?

Do I have an issue within the unseen control box? And can anyone help please?

In anticipation
Chris

 

[birdman101]

What voltage is the 12 volt element connection showing. If voltage is OK what is the element resistance showing.

 

[JTQ]

I assume it is realised that on 12 volts it should only work when electrically coupled to the tow vehicle with its alternator pushing out something above 12 volts?
The installation should ensure only this can happen.
Apologises if all this is known.

 

[Lost in time 1955]

Hi Birdman, I will disconnect the two wires and check for resistance.

 

[JTQ]

Not till you have checked it has not any resistance , proving its blown or hopefully not.

 

[Lost in time 1955]

Oh! Just found this on YouTube. Now I know a bit more and something to look at.

View: https://youtu.be/ONRqp9zRmC4?si=EIQO11WVDbWQVj8I

 

[Lost in time 1955]

I assume it is realised that on 12 volts it should only work when electrically coupled to the tow vehicle with its alternator pushing out something above 12 volts?
The installation should ensure only this can happen.
Apologises if all this is known.

Hi, yes it's the cars alternator that's giving the 14.2 volts. Thanks.

 

[ProfJohnL]

You do need to check the fridges 12V element is capable of working. If you can disconnect the 12V supply to the fridge and check the dc resistance of the element . The value you should see a reading in the order of 1 Ohm.

The reduced voltage at the relay, might indicate the cabling to the fridge is too small for the current which is causing the voltage drop.

 

[Lost in time 1955]

Thanks Prof, a few options to look at. It's a 2018 Bailey so I would like to think the wire rating is correct though. 👍

 

[Buckman]

Hi, yes it's the cars alternator that's giving the 14.2 volts. Thanks.

Does the car have a Smart alternator as many issues stem from that?