Just add a single heavier wire from the alternator to the starter. That
will probably fix your issue. A great vendor even sells a wire built
just for this purpose.

http://www.van-cafe.com/home/van/page_780_235/alternator_cable_upgrade.html

The junction you are looking for is in the engine compartment wiring
box. Left forward corner of the engine compartment. There is a threaded
stud inside where several red wires come together. I have seen several
of these with wire damage at that stud, mostly in models before 87.

Mark

Michael A. Radtke wrote:
> ..............
> So, I looked at the charging system and was reminded again that the
> Vanagon uses an alternator that supplies a constant voltage at its
> terminals instead of supplying a constant voltage at the battery. With
> the engine at 1000 rpm, I measure 13.8 volts at the alternator with the
> lights and heater blowers turned on, but only 12.6 at the battery. That
> is not enough to maintain the battery.
>
> It is most likely that there is a high resistance path in the wiring
> between the alternator and the battery. Bentley shows two parallel
> wires from the alternator that connect to a bus wire that runs from the
> heavy starter cable to the front of the Vanagon. I don't know why VW
> didn't run those parallel wires directly to the starter cable. I
> suspect the junction of the parallel alternator wires and the bus wire
> is bad, but I can't locate the connection. Can anyone tell me exactly
> where it is?
> .....
> Thanks,
> Mike
>