Not trying to be harsh but if the tech cannot answer these questions you
don�t have the right tech for the task. The temps 2 sensor for the ECU and
the sensor for the gauge are completely different. On the later vans, the
low coolant only causes the light to flash. The gauge pegging indicates a
bad sensor, a short to chassis in the sensor wire or something is wired
wrong. It should not that hard to trace the wires out and determine what is
wrong. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Anthony Egeln
Sent: Thursday, March 10, 2011 11:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: ECU & Coolant Temp Sensor

We've pretty much given up on attempts to repair the stock coolant temp
gauge & sensor system. �Have swapped out the instrument cluster, replaced
the sensor and walked the wire. Still pegging max high with a steady
flashing light, but the thermal laser gun reveals a normal temp system.
There was a posting recently on "slime" affecting the level sensor in the
pressure tank, and I plan to share that with the tech. �I suppose that would
only affect the blincking light anyway, not the temperature reading.�

The tech working on it has found a completely independent (of the stock
system) aftermarket coolant temp gauge and sensor and he plans to install
that over the next two days.
One thing is unanswered in my mind. �Does the stock sensor give temperature
readings to the ECU? �I'm wondering if this is one of the reasons why my
fuel economy has dropped from 18-19 to 16-17, i.e. running rich.
�Furthermore, if the ECU does get data from the stock system, how will the
aftermarket system get tied into the ECU? �
I haven't talked to the tech about this yet and wanted to get the ideas of
the list.
Thanks, Anthony'89 Syncro GL 2.1 (Hidalgo)�