All pins on the 15-way connector are common and connected to the 12 V negative block.
All pins on the 12-way connector are 12V positive, but…
:: 10 pins are outputs, fed from the block of six fuses
:: 2 pins are inputs from the leisure battery and are also connected to the charger
Hard to describe which two pins, but if you remove the six fuses and test each pin with a multimeter you should be able to identify them.
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