A6 2,6l V6: Normal engine coolant temperature?

[Ottar T]

>I got a German handbook (So wird's gemacht by Delius Klasing Verlag) that
>says if the voltage stabiliser is faulty, the reading of both the coolant
> temperature and the fuel tank gauge will be wrong.
Ruled out since the fuel indicator give normal readings.

>However the OBD-52 channel show segment F1 lit (coolant fan first speed ON) from >start-up of engine.
Normal when climate compressor is running! Pushing the Economy button shuts
down the fan.
The thermostate is working properly, opens some minutes after the climate
control indicates 90 deg C. No circulation trough the heat exchanger until
the thermostate opens.
The temperature indicator on the dash board indicates below 70 deg C while
the climate control gives 90deg C as a reading on channel 51.
This indicates a faulty temperature indicator or a faulty electronic
temperature sensor (F76 on circuit diagram, position 101/102). The brown
sensor is placed at the back of the engine on the right side. It has a
four-pin connector, blue/yellow supply to 4/C, brown/yellow signal from 1/T
to temperatur indicator, blue/green signal from 2/R to climate control
display and ground connection (brown?).
 
 The temperature gauge should be possible to test by disconnecting the
four-pin plug.
Ignition on with disconnected wires should give a fixed reading on
temperature gauge? What?
Ignition on and connecting pin 1/T to pin 4/C should give another fixed
reading? What?
Ignition on and connecting pin 1/T to pin ground should give another fixed
reading? What?

Measuring the resistance across the pins on the sensor should also give
different readings with cold or warm engine. What?

Anybody out there with a Service manual whiling to share information on the
above listed check points? I want to be sure what is  wrong as a new sensor
cost NOK 1100,- at the dealer (DM 275,- or ECU 138,- )

--
Ottar T
'86 Audi 80 1,8
'97 Audi A6 2,6