Although this pertains to an 83 rabbit, it could just as well be a vanagon.

Problem was first intermittent.  When turn key to start car--nothing, not
even a click.  Was able to start car by hot wiring solenoid, so it is not
the problem.  Also check continuity of wire from ignition switch to
solenoid--no problem.  Near as I can tell, the problem is a short or bad
connection or something in the switch/housing itself.  But how do I get in
there to fix it?  Sometimes when I disconnect and reconnect the wire
assembly from the switch it will start, other times it won't.  Hence, I
think the problem is in the switch/housing.  Any ideas?