The tank level and under sink wiring diagram is in Bentley.  Note:
You either need the '85 edition (VV85) or the current edition*.  The
'91 edition omitted that diagram. (You can find all the gory details
in the Vanagon forum on Bentley's website. See below.)

The water pump takes a ton of priming.  I usually end up applying a
bit of suction on the spigot to get it going.

Jim
another '82 diesel Westy

* VV91 that is currently sold by Bentley. At least Stan Wolfarth TOLD
me that they fixed it in the 2005 printing. For sure the '85 edition
has it.
<http://tech.bentleypublishers.com/thread.jspa?
forumID=49&threadID=1125&messageID=97755#97755>