What kind of sensor is this?

Hello,

When I open the hood of my Passat, there's a 'sensor or sender' clipped to the metal on the left side, near the pollen filter. For testing purposes, I placed the sender in the engine compartment to see if it was the outside temperature sensor, but it wasn't. According to the MFA (temperature display), nothing changes. What kind of 'sender' is it? Does anyone have any ideas?

Okay, the temperature sensor that displays the temperature in the MFA is located on the front left side of the car (when standing in front of the vehicle), inside the bumper and behind a grille.
Unfortunately, I don't know exactly what you're referring to.

"In my car, the sensor for the climate control shut-off at temperatures below 5°C is located exactly there (which can be easily simulated with a glass of ice water!). I have a manual climate control system. With Climatronic, it could also be the temperature sensor for the intake air inside the cabin."

Best regards,
Dirk.

On the left side, the height of the pollen filter has a 'sensor or transducer' clipped onto the metal sheet.

Yes, that is the temperature sensor for the water reservoir. The sensor for the outside temperature is located on the driver's side of VW vehicles, in the bumper below the headlight, within the nearest grille.

The sensor is used to determine the temperature of the air being drawn into the interior.

Thanks for the quick replies.

Okay, so far as I understand, this is the sensor that controls the (manual function in my case).
Air conditioning that shuts off at -5°C!

If that's the case, then moving the sensor to the engine compartment would cause the climate control system to run 'longer,' effectively simulating a higher temperature.

Is that correct or not?

Best regards,

Yes, that is completely correct. But what benefit do you expect from it? A climate control system cannot prevent condensation on windows in the winter as long as there is a temperature difference between the evaporator and the surrounding air. The humidity in the air condenses on the coldest surface – the evaporator – especially in the summer. In addition, ice formation can occur, which certainly does not contribute to the lifespan of the evaporator due to the expansion (of remaining) water.
Best regards,
Dirk.

Hi,

Okay, I hadn't even thought about the possibility of moisture forming at the 'coldest' point.
stops. Could it really be that the refrigerant is freezing up???

Das könnte nicht nur so sein, das ist auch so. Nicht umsonst schaltet die Klima ab. Allerdings gilt hier auch je kälter es ist, desto schneller friert es log. Wice cream.

Could you please tell me what sense you think this makes?

The refrigerant is unlikely to freeze, but the condensation on the evaporator might.

My CT doesn't seem to be as sensitive to the +5 degree mark; it continues to run even at +2 degrees. I observed this recently. It wasn't until .5 degrees that it started to hesitate during faster driving, but then at the next traffic light, it engaged again even at .5 degrees. Below that temperature, however, the compressor really does shut off completely.

"//edit:"

@turgumu:

In this technical article https://community.dieselschrauber.org/en/viewtopic.php?t=6956, you will see which sensors a CT has. This includes one in the intake manifold, located in the water collection box. Some of these sensors are also present in systems with manual climate control.

Oops, that's actually what I meant. R404a (as an example) freezes and becomes solid at approximately -104°C and 1013 mbar, which is normal atmospheric pressure. However, it only stays in that state once; when thawed, it will decompose into its constituent components.