Hi,I've got a 1996 Hymer B564 which was imported from Germany in around 2000. The control panel above the 'hab' door has a number of switches on it, most of which are self explanatory. However, there is a rocker switch to the right of the battery test switch that I don't know what it does. The upper position is labelled ' Reserve' and the lower position 'Aus'. Has anybody any ideas? Regards, Ralph Sorry posted to wrong forum!