Does anyone know what Mercedes Benz calls this part circled in the attached picture? Thanks.

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engine temperature sensor I think. I know that one controls Aux Fans(electric ones).

Auto Climate Control thermistor temp input sensor.

http://catalog.peachparts.com/ShopByVehicle.epc?q=1994-Mercedes--Benz-E3--0--Sedan-Climate--Control&yearid=1994%40%401994&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6391%3ABT%7C5%3AMBC%7C1508%3AED%7C10000022%40%40E320+Sedan&catid=242213%40%40Climate+Control&subcatid=242256@@A%2FC+ACC+Temp+Sensor&mode=PA

The ACC module is N22 and that sensor is that modules Input Temp signal. The N22 then decides on the different functions of the system...one being the High Fan trigger and another being the ac compressor cut-out temp spec.
So, it controls different functions and is not just an aux fan sensor.
Rather , it is a control modules temp Input sensor, and it is a Neg Coefficient Thermistor, meaning it's Resistance decreases as the temp increases. ..and that change in R factor is the value factor for each of the modules trigger circuits.

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A Dalton

Thanks. Only the part in the catalog does not match. Mine has four connector pins on it. When I disconnect the cable from this sensor, my aux fans kick right on at high as they should. But they will not kick on at any temperature at low or high. 30 amp fuse is good on the relay, fans do kick on in the low setting when A/C is turned on. What else to test and how? This is on a 95 E320 which has the coil wire resistor. Does my car have a pre-resistor that could have something to do with it? Thanks in advance.

There was a change in that sensor as of mid "95 E class production.

So, now you know why we like you to tell us the model/year up Front.

Anyway, same deal..except it is two thermistors in one casing.

The high fan comes On when you disconnect the connector b/c the ACC panel Module has a default circuit to trigger high fan for over-heat saftey in case sensor goes bad to prevent a motor Lunch from over-heat due to bad sensor or wiring....so you are simply causing that faulkt when you unplug...simple as that..and knowing that feature exist allows us to use that unplug for a quicky test to verify High Fan circuit.

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A Dalton

< But they will not kick on at any temperature at low or high. >

If you have high fan w/default, then you have verified the high fan circuit [ except sensor]
Just remember , high fan does not trigger until 107C,

Do you have 107C ???????????????


..and forget low fan..it has Nothing to do with temp..it is pressure sensed.

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A Dalton

You have excellent insight Arthur, very quick to respond too. Thank you very much for your help on this so far; really appreciate it.

To answer your question regarding temperature, yes, it went to 110c (right where the blue line is in the picture) yesterday and the aux fans did not kick on. I had to turn on my heat full blast to get it to come down to 100c. My car's normal operating temperature since putting in a new thermostat has been about 100c. I would like to fix whatever is malfunctioning #1, and then i would like to professionally install a resistor that tells my aux fans to come on at low speed when I hit 90c and to come on at high speed when I hit 100. Unless, you recommend against this.

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This is the later sensor

http://catalog.peachparts.com/ShopByVehicle.epc?q=1996-Mercedes--Benz-E3--0-Climate--Control&yearid=1996%40%401996&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6393%3AMBC%7C1575%3AED%7C10000023%40%40E320&catid=242213%40%40Climate+Control&subcatid=242240@@A%2FC+Temp%2E+Switch&mode=PA

If you have default,,but no high fan @105/107, then the sensor is suspect.
Before going with a bridge resistor, you should check the R value of your sesnor against the temp chart.

I can post that later.

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A Dalton

If you just put in a new thermostst,then the suspect is the car has an air lock...try burping the system..if there is a lock, then the aux fan sensor is not reading coolant temp correctly b/c that is where the air lock is...burp the top hose w/cap open at temp ..slow squeezing with a gloved hand after thermo opens

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A Dalton

The low speed is controlled by the red colored sensor on the A/C drier which comes on when a certain pressure is reached when the A/C is on.

OH..Okay.....................................

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A Dalton

Yes! That is the correct part, nice!

And I would be interested in looking at the temp chart. Ideally, what is the best temp in your opinion for the fan to turn on? Is it possible to get the fan to come on at low speed settings based on a 90c temperature, even though they only turn on low speed with pressure? If so, how?

Correction, I would say it's only averaging 100c on days where the outside temp is 80f plus. Otherwise, it's around 95 average. The thermostat was put in about a month ago, and since then I had some work done on it where the coolant was changed by my mechanic. But I will try burping it. With the old thermostat in, my car would take a while to get to operating temp and it would stay around 80 during late Spring. With the new T-stat in, it immediately went to 90c after warming up and my car seemed to run better and pull harder; I liked it. But with my fans not coming on at 105 or at all except when the A/C is on, it is going over temps that I am comfortable with. I would rather keep it below 100. What is the ideal temp for our engines for longevity and fuel economy? Thanks.

You are at normal with your temps but I dont like my motor that hot so that is why I put a 1.1K resistor in parallel with the wires to trick the high speed fans to come on sooner that keeps my temp from 85-90.

That's what I am looking for, what wires are you putting the resistor on and are you leaving the wires still connected to the sensor they plug into or have you removed them completely and then jumped them with the resistor. At what temp do the aux fans kick on with your setup and will it work on a 95 with the way things are setup a little differently? What is the voltage of the resistor you are using? A picture of your setup would be great. Happy 4th. Thanks.