[ChuckS]

At 2 years of age the GC2 batteries should be in excellent health provided electrolyte level has been maintained and proper charge...

A quick specific gravity check with tell the story with the batteries... if yo7 dint have a hydrometer any auto parts store will have a low cost one you can buy..and should have

I’d remove those battery cables and clean the posts and cables with wire brush and reconnect. Also check DC connection from battery to DC bus bar and ground connection from battery to chassis ground.. remove that ground connection and clean it...

Visually looking at connections tells you nothing... physically cleaning them is only way you will know what you have

My GC2 batteries are 4 years old on my fifth wheel..
I can run the leveling system several times without shore power and have no issues

And yes...if the 12 volt source to the level up up control panel or control module drops below 12 volts for even just a second or so during “auto level” you will error out...

These should also be a red wire from battery post directly t9 the level on control module.. not the panel. It has an inline fuse...remove fuse and clean fuse connections and also reseat that single red wire on the control module itself.