Thanks to all the suggestions.  It was a bad ground.     Fixing took
me about 2 hours: I had to drop the fusebox, pull the instrument
cluster and move two air ducts to even get access to the ground
"crowns", and even then I was working somewhat blind.  On my van the
grounds are really hard to reach even after you move all the junk out
of the way.   Anyway, when all was put back together, it works great.

After doing this job, I'm left with the feeling that the electrical
system in this beast wasn't so much designed, as grew through a
process of slow evolution.   Start with a normal fuse box.   Then,
later, they needed some more fuses, so they added an extension to the
fusebox.  Nevermind that it kinda runs into the steering column and
uses a different style of fuse.      Then they needed some more
relays, so they added one to the wall.    Oops, need a few more!
Let's add some over here.  And here!    And, of course, the final 2
fuses which the westy owners know about, on the drivers door jam.