Is this setup the factory-fit aux battery wiring?

[rover220]

Why would a tow bar be connected to a leisure battery? I have an aux heater so it could well be for that

Because factory wiring doesn't work like crap bypass electrics

 

[mmi]

Why would a tow bar be connected to a leisure battery? I

Can run trailer ancillaries from van's aux/leisure battery. It prevents flattening van's main/starter battery (when engine is not running).