Empty the tank and scrub the sensors (bolts) with hard Scotch-brite (green
color) or fine sandpaper.  Clean and rinse thoroughly and test.  If still
not good, add 2-3 grams of salt (2-3 ml) to a full tank and stir it in.  It
will make the water more conductive.  If that works and the taste is ok,
just add a little salt before you fill the tank.  If not or if you don't
want to add salt, look at the water-level circuit at
http://pws.prserv.net/synergy/Vanagon/LEDpanel.htm -- there is a 100 k-ohm
resistor that goes between pins 5 and 10 of the left-side IC.  If you can
find a small 1-megohm potentiometer, wire the center and one end across
this resistor and adjust until the yellow works and the other lights are
still correct.  Otherwise get a full-size pot and clip it on temporarily
(pot and test leads available from Radio Shack).  Find the two ends of the
adjustment range that work correctly; at each one remove the pot and
measure the resistance -- make sure you measure from the same end that
you're using.  Get a resistor assortment or buy a resistor that's as close
as you can to halfway between those values and solder it in instead of the pot.

If you're not comfortable with electronic soldering, find someone who is,
or practice and learn to solder -- this is an easy board to work on but you
still have to do it right.  See the picture on my web page for example of
how a neat job should look.

david

At 09:20 AM 5/30/2002, Dje Mobile wrote:
>i have a problem with the water level indicator light (green, yellow and
>red). When the tank is full, it's green, (no problem)
>when the tank is between the upper sensor and the one below, the yellow
>light don't work and the red light is on instead of the yellow one
>(problem!). when the tank is empty, the red light is on.(no problem)

--
David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"