12v Fridge Feed - ?6 Code Fault

[SnJ]

***HELP PLEASE***
Anyone have an idea where the 12v feed from the vehicle comes from when started??
I get a ? 6 fault code when the MH is started up - this means that there is no supply from the engine)

There are 5 wires that are connected to the fridge for 12v supply
Red +12v (provides 12v to fridge)
White -12v
Orange 12v signal feed when engine is started
Purple +12v (powers display on fridge)
Black -12v

Have tested all of these with & without the engine running and the results are this
ENGINE NOT RUNNING
Red/White = 13.32v
Orange = 0v
Purple/Black = 13.32v

ENGINE RUNNING
Red/White = 10.32v
Orange = 10.32v
Purple/Black = 13.32v

Fridge voltage parameters are 10-15v so am assuming that 10.32v is insufficient to kick 12v relay on PCB over to 12v power
Spoken to Thetford direct and have tested the fridge (as suggested by them - great customer service BTW!)
Have completely disconnected the fridge, obtained a brand new AGM 12v battery and wired direct to it .
(RED/ORANGE together and connected them to positive / WHITE to negative)
The fridge works fine - does not display a ?6 fault code
Therefore it's a feed issue
Have pulled & tested all the fuses in the engine bay
Does anyone know where the feed from the engine comes from (alternator??) or if there is a fuse/relay I have missed
Cheers
Rusty

Have attached some screenshots for reference
(ignore the bit on the Norcold pic about the ARP wiring - that's not on this fridge - I used it to see how the block connector plug is wired)

 

[sally47]

Don't know if any help but I had same probs if you have a fiat just below the battery is a see thru plastic box with three fuses I think it's the top one that operates the fridge 15amp mine kept blowing was told by service dept should be 20amp so replaced all ok since good luck

 

[SnJ]

sally47 - thanks for that.
I should have put in it's a 2009 Fiat Ducato Autotrail Dakota 3L