Rapido fridge 12 volt fault

[mark.supra]

The fridge light on my Dometic 3 way fridge flashes red when the engine is running but works fine on hook up and gas.
I have replaced the main 20amp fuse but I believe there is another smaller fuse and a relay somewhere but I can't find them.
Any help would be greatly appreciated.
My Motorhome is a 2004 Rapido 962m based on a Mercedes sprinter

 

[Alanedwin]

I had a similar fault on my sprinter based van. It was just before I found out that I needed the alternator replaced. It could be due to the battery condition.
It disappeared after the new alternator was fitted.