The sensor which I think is for the AUX fan


The sensor which I think is for the Temperature gauge


Both sensors in my car.
Hello.

I have a W124 E300TD with a temperature gauge behaving very oddly. Sometimes when I drive the gauge shows normal and then it jumps to over 120 degrees Celsius and stays there and then after a moment it goes back down, and up again.

I'm guessing there is a electrical problem maybe a faulty solder in the instrument cluster, because the fuel gauge is behaving weird sometimes as well. The fuel level goes to full and then goes to where it's supposed to be when I knock on the cluster, but that's another discussion. I'm going to post a new thread about the weird electrical problems in my car.

Photos are attached to the thread.
I tried changing a sensor that someone on a parts website told me was the one I needed to change. I soon realized that there are two similar sensors. one with two pins and another with one pin. Can someone tell me what these sensors are for, and is one of them for the temperature gauge in the instrument cluster?

After I changed the two pin connector sensor, the AUX fan goes spinning very fast after a short drive. When the engine has had moment to cool down the AUX fan does start spinning when I start the engine again. If I take the plug off while the engine and the fan are running, the fan stops right away, and starts turning if I plug it back in. I never heard the the fan when I had the old sensor in.

I'm thinking that the sensor is not the right part for my car as the fan starts very quickly and runs very fast even when the engine temperature seems right.

What are these sensors for?
Are there different types of sensors for different types of engines of this car? Like if the sensor is made to turn on the fan on at lower temperatures than it's supposed to.

If you have any questions please feel free to ask.

Thank you

 

I recently bought the car, so I don't know when the last time the engine was flushed and the thermostat got changed.
Haven't thought so much about this, because I think the problem is electrical.
The VIN number is: WDB1241331C094421

 

Then how come the AUX fan turns off when I take off the two pin sensor?
And I think needle in the gauge falls if I knock on the IC.