Hello,
I have checked the wires, haven’t found loose connections.
There is no dedicated fuse for the fridge, and as I see the others are also OK. Unfortunately I don’t have a multimeter (and the knowledge what to measure and where 
).
I think the battery is not an issue, it is 1 year old. When it’s fully charged by the charger on grid, the fridge starts but then stops (see my test yesterday).