Leisure batteries not connected to each other

[BenCar]

Need some knowledge please forum:

I've a solar system connected to the rear leisure battery, works v well and I can monitor on the app.
It seems that the front leisure battery, which is shown on the control panel, is having a hard time. The readings between the 2 are wildly different. It's obvious the solar power isnt getting through to the front leisure battery. ChatGPT tells me that the connections between the batteries is broken. I've replaced the 80amp fuse under the passenger seat but it's not done anything.
Then ChaGPT went crazy and had me looking under the bonnet, which it then admitted was a mistake.

Anyone have further ideas for me to check next please?
Thanks
Ben

 

[WelshGas]

Need some knowledge please forum:

I've a solar system connected to the rear leisure battery, works v well and I can monitor on the app.
It seems that the front leisure battery, which is shown on the control panel, is having a hard time. The readings between the 2 are wildly different. It's obvious the solar power isnt getting through to the front leisure battery. ChatGPT tells me that the connections between the batteries is broken. I've replaced the 80amp fuse under the passenger seat but it's not done anything.
Then ChaGPT went crazy and had me looking under the bonnet, which it then admitted was a mistake.

Anyone have further ideas for me to check next please?
Thanks
Ben

75 amp cube fuse on the +tve terminal of the rear leisure battery.
The 80 amp fuse under the seat , by the front leisure battery, is on the supply from the alternator.
If the cube fuse fails the 2 leisure batteries are separated so solar will charge the rear battery and alternator will charge the front. All leisure power is connected to the front battery.