This post reminded me.................
And time there is gage weirdness, consider the Voltage stabilizer in the
dash - a small  gizmo, about the size of a thumbnail. Mounts with one screw.

Fixed a lot of dash and gauge weirdness replacing those. 

If you went black & white, from not starting well cold, to starting well
cold, and that's the only thing you did, replace the ecu temp sensor, then
that musta been it.

  I've never bothered, but it would be great to have a resistor to just flip
a switch for, and it would replace the ecu temp sensor - , sort of an
emergency default resistance reading, for testing reasons and
troubleshooting.  I've always wanted to wire in a redundant fuel pump too ,
but haven't ever needed to.   I do like the idea of readily being able to
switch in some value that will take sensors out of the picture temporarily.
I love understanding things well enough to be able to trick them to work my
way, when I say.  

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Allan Streib
Sent: Wednesday, November 28, 2007 9:19 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Changed thermostat - temp gauge still reads stone cold

On Nov 29, 2007, at 12:05 AM, syncro.carboncow wrote:

> I would disagree. Good for a couple of
> years? They often go 15+ in our vanagons
> before failure!

Well maybe I had a string of bad ones.  I owned my Jetta for about 10
years, and in that time I replaced the ECU sensor at least three
times and the gauge sensor twice.  The failure modes were very low
reading on the dash gauge even with the engine fully warm, or very
hard starting of a cold engine but a warm engine would start easily.
In my PERSONAL experience the sensors are a definite weak point.

> Again I've talked to the sources and
> although the failure of a new sensor is
> not impossible it is uncommon.

I missed that part of the thread; I agree if the sensor has recently
been replaced it's POSSIBLE, but not likely, that the new one has
already failed.

Allan