Car Temp and Windscreen wipers

[chutzpah44]

How does my car (Audi A4) know what the temprature is? Where is the thermometer?

Also I have my windscreen wipers on auto. Obviously it does not come on if the windscreen gets wet as sometimes I go over a puddle (when its not raining) and they give a few wipes

 

[Fazda]

As far as I know the temperature sender is located somewhere under the front mudguard where it is not too affected by variations in temperature...good question...I haven't a bloody clue!!

 

[gifs]

The rain sensor on my Jetta is located in the windshield, behind where the rearview mirror is fixed to the windshield.

Here is how it works from wikipedia:

The most common modern rain sensors are based on the principle of total internal reflection: an infrared light is beamed at a 45-degree angle into the windshield from the interior — if the glass is wet, less light makes it back to the sensor, and the wipers turn on.