coolant temperature sensor
 

Is there more than one coolant temperature sensor.? Does the ECM and the temperature gauge on the dash use the same sensor?

I believe there are two, one on the back side of the motor, and another on the radiator, I have a 2000 a4 quattro, and this is where my sensors are, hope this helps

new data
 

Thanks for for your comment.

I now have new data. The gauge has been intermittent, reading normal or full cold. I just got home and the gauge was still reading full cold, I connected my vag-com and reed the coolant temperature with measurement group 4. It was 98 C, which is a perfect operating temperature. Thus the sensor the ECM uses is working.

Thus my question is where does the signal for the gauge in the dash come from. Directly from its own sensor, from the ECM, or from somewhere else?