Have a look at your fuse panel. Do you see a non stock looking #10 or
#12 wire with an inline fuse holder connecting to an empty fuse spot?
Does a red wire connect between the starter battery and aux. battery
via isolator, fuse etc.?

On Westies (and weekenders too?), a larger red wire from the 30 buss
of fuse panel (battery "always on" power)  supplies power to the Westy
appliances (sink pump, light, fridge). Some of us have repurposed that
wire to take + power FROM the driver seat aux. battery back TO the
fuse panel. The exact spot and wiring scheme varies depending on model
year but if one fuses that wire, it can be used to supply power from
aux. battery to stereo, interior lights, and possibly added 12V
outlets as long as the wire gauge can handle
the load of all appliances if used at same time.

To do so, a new + wire from the vehicle charging system would have to
be installed.
Most would connect a wire from the starter battery + post
to the aux. battery via isolator fuse etc.

On 7/8/15, PB <pbrattan@gmail.com> wrote:

> By the way, while my starter battery was removed from the car, I discovered
> that my stereo, dome light, and fluorescent light all worked. I don't know
> if that means that I already have this kind of battery relay system
> <http://www.gowesty.com/ec_view_details.php?id=2418&category_id=&category_parent_id=>
> installed.

--
Neil n

Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca>

1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy>

1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/>

Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>