No 12v feed to Thetford fridge freezer chausson 610 2016

[Bramleyestate]

Hi there, I'm going mad trying to identify why my Thetford fridge freezer has no 12v supply, works fine on gas and mains 240v hook up.
The motorhome is a Chausson 610 2016, Victron solar charger 100/20 and Victron Orion 12/12 18 DC Charger fitted. New ish lithium battery. Boite Relais securite is located in cupboard behind drivers seat with the Orion charger, appears to be working correctly under test.
However removing outer lower fridge grill, I have no 12v power, this Fault is combined with when trying to read the battery state on the PC180-TR control panel, the vehicle battery charge does not display other than 1 bar. I have been driving and running the engine lots and there is no shortage of battery power. The habitation lithium displays a full charge and is working correctly, in fact everything else on the control works correctly.
When I purchased it, the usher informed me someone had told him a relay was missing?
All fuses, I have so far found, are all ok.
Ice just read about I've being near the lithium battery so will have to check that.
Any ideas would be greatly appreciated, my electrician has just spent 2 hrs I've it and not found the fault so far!
Thanks very much Jules

 

[Bessy765]

With respect when selecting 12 volt it only becomes live when the engine is running

 

[IRHP]

You don't say what model of fridge you have but this is the wiring for some of the Thetford 3 ways. There are 2x12v feeds. One high current , one low for controls and a D+ from the alternator. They are both live but the d+ only being live when the engine is running tells the fridge to run on 12v. It should just be a case of finding where the the high current feed comes from.
Others work via a relay that is operated when it gets the D+ signal so there will be no 12v feed unless the engine is running, d+ is live and the relay is operated. Find out which you have then you can investigate better.

 

[IRHP]

With respect when selecting 12 volt it only becomes live when the engine is running

Not always. I have a permanent high current 12v feed to my fridge. Thetford N3142. The D+ from the alternator goes to the fridge pcb and it then uses the high current 12v feed when the D+ is live.