Just catching up on e-mail and hope this situation was remedied.
I didn't see any mention of what transmission is involved here but some
words of experience from someone who's been there more times than preferable
with the AUTOmatic transmission.

The automatic transmission starter solenoid gets it's juice from the
Park/Neutral safety switch located under the plastic shifter housing.  This
switch is of the general type that is made of plastic with metal contacts
built on the side that is jumped by a thin copper type metal piece that
moves along the side by way of the shifter handle.  This thin copper type
metal piece is all that bridges the juice from the electrical system to the
starter solenoid.  It's tension against the plastic switch is held by a
small spring as it glides over the switch making contact between electrical
contacts as the gear shift is moved between gears.  This switch IS going to
fail eventually.  I've replaced several in the 5 years of wasserboxing and
have recommended this repair to countless listees who have found it to be a
problem with their particular van as well.
Please note the following quick check:  checks are done with e-brake set,
key in ignition
*Does the van start or starter engage for a moment if the shift lever is
moved a bit while attempting to start?  Try Park then Neutral.
*Do the reverse lights work?  Will they if you jiggle the shift lever?  key
must be in ON position to check
More thorough check:
Do you get at least 10.5 volts at the solenoid wire while attempting to
start?  Is it constant or can you affect the voltage readout by jiggling the
shift lever?

If you find any of these symptoms or problems with an AUTOmatic transmission
Vanagon, likely the Park/Neutral safety switch is suspect.  Vanagain.com has
availability on the switch and it's metal sliding contact for around $30-35
IIRC.

ps...this would be good fodder for the FAQ.

JB
'89 Wolfsburgs...yeah 2 of them, both automatics with replaced P/N safety
switches as needed