adrianbutter wrote:Think I may have used poor english - or I am confused.
Adrian
I think there are three things going on
1. You have a glass fuse instead of a blade fuse, the ratings of which mean different things
2. The fuse you have is the wrong size
3. VW wiring is different to what is perhaps the ideal - but is still effective.
Having the batteries connected in the engine run position for a couple of seconds while you start the van isn't a problem. (except perhaps in a situation where there one battery is fully charged and the other is flat. - but that isn't the problem you are describing)
Change the first two, then armed with your new multimeter watch the leisure battery voltage as you go through the starting procedure. Unless someone has been messing you should get answers along these lines.
Off.... 12.6 volts (an assumption)
Engine run... could vary from 12.6 volts according to main battery state
Engine start.... 12.6 volts (batteries no longer joined)
Engine running.... around 13.8 volts, perhaps more