Audi Repair: 02 Audi S4 (APB) 2.7T Outside Temp Gauge, external temperature sensor, radiator grille

Question
Hello Jan,
My Outside temperature gauge will often drop to -25F, and then slowly work its way back up to the correct outside temp.  Most Recently on a 3Hr trip, it would drop to -25F, work its way up 40 or so Degress, then drop back to -25.  (Real Temp was 80F)

This was mildly amusing in the spring, but it is used by the A/C which won't work below 0.

I have the ETKA, and Bentley's CD-ROM, but can't figure out where the sensor is located, and how to remove it / check for tightness. I do not have VAG equipment, but wanted to see if a (Maybe wet/loose) $35 sensor would be the culprit.  Your thoughts please

Thanks in advance!
Mike


Answer
The external temperature sensor is usually in the front radiator grille or sometimes just behind the front bumper.  These sensors are quite frequently the problem since they sit out in the weather, usually a good cleanup of the contacts will cure the problem.  Look for a small plastic module clipped in place with a couple of wires going into it, and a small sensor in the front.  Good luck,  Jan