Camping display dead and roof up California T6.1 Ocean

[JPVW]

Hallo I am from Netherlands and I have a problem with my 2020 California, a T6.1, after standing for about one month with the (hydraulic) roof up the, all the 3 batteries were nearly dead. After charging them the display of the camping unit stayed black and I couldn’t operate the roof, willing it to close and drive.
After reset of all the fail codes in the board computer it still doesn’t work. Any ideas what I can do now? Thank you all for reaction.

 

[Stargazing]

Have you tried running the engine?
Try pulling out fuses - I think they would be located to the left of your steering wheel (presuming you are LHD) I recall reading that the T6.1 has an upgraded vehicle control unit covered by 4 fuses.
Try pulling out these fuses (25 amp all aligned together) numbered 5-8 to see if that works.
If successful, give it a good run too.

 

[Hawthorn37]

I suspect that one or both of the leisure batteries have been damaged. I’m sure you will find threads about testing the leisure batteries - it’s a fairly common topic.