I have an intermittent problem with my 1991 Volkswagen Vanagon GL
Campmobile with original Waterboxer 2.1 engine (180K miles) starting.  Most
of the time it starts just as it should, almost as soon as I turn the key.
On some occasions, more often when it has not run for a few days, but not
always that condition, nothing happens when I turn the key.  I can hear the
fuel pump running, but warning lights do not come on every time, or if they
do, I (dumb, I know) failed to notice.

My mechanic, European AutoHaus in Spokane, Washington ("Obie," trained on
these things in Germany, and almost as old as me with long experience with
them), cannot get it to fail in this way.  Starts every time for him.  I
have an ignition switch in the engine compartment as well, to use when
working on the vehicle.  Obie recommended that next time it fails, check to
see if the  engine bay switch works.  If not, he says starter, if yes, he
says ignition switch.  He states that the steering column ignition switch
looks fine (not discolored as his experience tells him is usual when the
switch is bad).

Thoughts on this matter from this community of experts?

Thanks, David McNeely