operating temp / gauge question...

[Ottar T]

|under normal operation, my gauge sat in the middle almost all the time, a 
|bit less in winter. In traffic it would climb above the half point, but not 
|by much. I had a new radiator put in when I bought the car. But the weird 
|thing is, when my rad. fan switch got shorted and the fan ran all the time, 
|the temp would stay below the 1/4 mark, esp. on the hwy. I would've thought 
|the thermostat would've closed, but it didn't. Maybe the thermostat worked 
|ok, but couldn't completely stop coolant flow. In any case, I think half 
|way is where it's s'posed to be for optimal running, winter or summer. good 
|luck.

On our A6 V6-12 the temp gauge stay at 1/4 low, but the Display on the climate control indicates 90c, i.e. normal temp. Both indicators receive signal from the same sensor, but with different wiring. I have tried to trace what ohm the sensor should have during testing, but nobody has come up with  the figures. Could also be the gauge itself that fails, so figures for testing the gauge would also be interesting.
Anybody in the list w/ info about ohm on temperature sensor/ gauge?

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