Date:         Tue, 12 Sep 2006 20:07:17 -0700
Reply-To:     Charles McGehee <chasm@ELLTEL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Charles McGehee <chasm@ELLTEL.NET>
Subject:      Re: Blinking coolant level light - Success!
In-Reply-To:  <7.0.1.0.0.20060911183637.01d7cff0@elltel.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed

Yes!  Success!  It was the capacitor in the temp gauge.  The best
message in the archives was one from David Beierl, June 10,
2006.  For the record, here's the link:
http://gerry.vanagon.com/cgi-bin/wa.exe?A2=ind0606c&L=vanagon&D=0&P=29956

A few tips, however:  It isn't quite as simple as David suggested in
that opening the temp gauge case presented a few challenges.  There
are some pressed fits and Chinese puzzles in there.  After I took the
needle and face plate off the tacho, I discovered that the unit is
actually split into two parts so that you can simply remove the
bottom half without disassembling the whole thing as I did.  Okay,
live and learn.  Beyond that there are some pins connecting some
points on the flexible printed circuit with the instrument
cluster.  Be Careful.  Be Very, Very Careful.  The thing tears
easily.  I had previously tested the voltage stabilizer which turned
out to be okay.  Bentley shows how to test it and what values it
should produce (p. 90.18 for the '85 but I think the system was used
by other years as well).

Taking the gauge apart involves not only drilling out two rivets, as
David indicated, but also prying off a fiber retainer on the
back.  Getting it back on was somewhat of a bear, and I wound up
tearing one of the holes.  So again, be Very Careful.  Inside there
is a little circuit board with a transistor chip, some resistors, a
red LED, and a capacitor.  The board is attached to the temp needle
with a wire about the diameter of a hair.  So, again, be Very
Careful.  I didn't remove the wire, betting that I wouldn't break it
(I won this bet, but it's the first in a long time.  I'm not known
for precision, you should know.)  The capacitor is a 10mf 16v radial
job.  As far as I can tell, there's no easy way to test a capacitor,
so I just replaced it with a 10mf 30v from Radio Shack.  (They didn't
have a 16v.)   The capacitance must be identical, but the voltage can
be higher (not lower).  It cost all of  $.99 plus tax.  The 30v was
slightly longer than the 16v, and since space was limited and there
was some sort of a piece of metal there related to the temp needle, I
had to make the leads longer and bend the thing to fit.  Be sure to
use a de-soldering bulb or wick to reduce the amount of heat on the
circuit board.

I epoxied the drilled-out rivets back in place and also mended some
previous fractures in the instrument housing with epoxy. Put the
thing together, took it for a spin and -- voila! -- it works.  Red
light blinks for about three seconds and promptly goes out regardless
of whether the engine is cold or warm.  I don't know, of course, if
it comes on when the engine overheats, so I'll be keeping an eye on it.

You guys are great!  Thanks so much for your sage advise and
willingness to help.

Charles
'85 Westy

At 06:43 PM 9/11/2006, Charles McGehee wrote:
>I'm desperate.  No burned wires.  Coolant level sensor good. Temp 2
>sensor good (or so says my mechanic), level control module good.
>
>But here's a puzzle.  When I turn on and turn off the headlights
>rapidly, the blinking light often goes out (not always, but
>often.)  I thought that maybe that indicated a drop in voltage which
>was affecting the light and maybe the voltage stabilizer on the back
>of the instrument panel was screwy.  Checked it out, though, and it's
>okay, too.  (9.8-10.0 v, well within Bentley's specs.)
>
>So, where do I go from here?  Any ideas?  I'm totally beat.
>
>Charles
>'85 Westy
>
>At 04:40 PM 9/7/2006, Charles McGehee wrote:
>>Here's where things stand with my blinking coolant level light:
>>
>>All grounds clean and sound.  Coolant sensor works.  Replaced the
>>coolant level control module (relay).. No change.    So I threw up my
>>hands and took it back to my mechanic.
>>
>>Unfortunately, it's not clear how much he knows about what.  He
>>thought the coolant control module was on the printed circuit behind
>>the instrument cluster and said I had replace the wrong thing until I
>>showed him the part and he called VW verifying that what I replaced
>>was in fact the coolant level control module.  In any event, he said
>>that the light would stop blinking when he turned the headlights on
>>and off repeated.  They he wiggled on the wiring harness which runs
>>across the back above the muffler.  He discovered that it was melted,
>>or at least the plastic cable retainer was sort of melted.  After he
>>wiggled on it, the light switch routine wouldn't work any more.
>>
>>He determined, then, that my relay is working and current is coming
>>out of it, but it's not being received by the flashing light unit,
>>apparently.  He's convinced that the problem lies either in the
>>printed circuit on the instrument cluster unless the "melted" wiring
>>has caused some sort of short or current leakage  .  So I told him to
>>put it back together again, and I'd look at the wiring harness before
>>committing to a new printed circuit.  This is where it stands now.
>>
>>What do you all think of this?  Have you ever had the rear wiring
>>harness melt?  It's in a stupid place, I must admit, but still.  Have
>>any of you every had problems with the printed circuit behind the
>>instrument panel?
>>
>>Would appreciate your views.  I'm at my wits end.
>>
>>Charles
>>'85 Westy