arnaudov

Hello, I have a very strange problem and I couldn't find a solution anywhere... Hopefully someone here can help me fix the problem I'm having.
It's the car Mercedes W211 E320 CDI 2009. OM642
It all started a year ago, it didn't matter if the air conditioner was on or not every now and then the fan would just stop blowing, it did it very rarely but over time it started to stop working all the time until it stopped completely.
I first changed the motor under the glove box + the hedgehog board that is on the motor for the revolutions - the problem remained.
I ordered a new climate system control from EBAY after the change everything worked for about 3-4 days and the numbers started again.
I went to 2-3 technicians with diagnostics, one said that he retrained all the modules of the car and then I had no problems for about 4-5 days and then it works again when it wants to...
Usually in the morning when the ignition is turned on it does not blow at all, after the car gets up to normal engine temperature about 20-30 minutes of driving, the heater comes on and starts blowing. Sometimes even at startup there is an air conditioning system and while driving it turns off and on when it wants.
Sometimes when I drive on the freeway everything is fine and after stopping for a rest and going again the two end nozzles blow warm at the last degree of power and the middle nozzles blow cold.
Another strange problem when the fan does not work, that is, it does not matter if the air conditioner is turned on and at what temperature and degree it is, and I turn off the air conditioning system from the panel, after a while it starts blowing and the control display shows that it is turned off. That is, it has remembered the last commands given to it, and when it decides to appear, it starts blowing regardless of whether it is stopped by the button.
Winter is coming and no craftsman can tell me what my problem is, I am asking for help and opinion. Everything has been changed since the circuit (control, fan, fan stages module)
Is there another module connected to the system and if so where is it located? What else can I try? By the way, in the summer, my air conditioner blows very weakly cold and it is not good, when I took it to have freon poured in, they told me that the system was full, but there was a lot of back pressure, whatever that means.

What else is this fan connected to and what controls all of this as long as the main module with the display that it is is not problematic?

I would be grateful for any opinion

arnaudov

This morning it did the following: It was about 9 degrees celsius I started the car and the fan wouldn't blow. After 5 minutes it came and started blowing normally warm as I had done and after another 3-4 minutes it stopped again and didn't come again.
This is the regular number and if I drive a little more like 30 minutes without turning off the car and it starts blowing in most cases.
Winter is coming, and in the morning without heating the windows, the mirrors, nothing can defrost...
After I have changed the control with the buttons and tried with another motor + another speed control which is located on the motor and the problem is not fixed, I don't know what else to try.
I read about similar problems with colleagues on the forum, but no one wrote anywhere that they solved the problem, or if they solved it, how it happened.
I will be glad if someone writes with assumptions or solved a similar problem.

nd-photo.nl

Maybe inspect the various temperature sensors? Do they give back normal values?

-the ambient temperature sensor
-temp sensor under the steering wheel
-temp sensor in the overhead control panel
-temp sensor in blower housing (also accessible under steering wheel)

ot1

seem that you need to invest in a Star clone to analyze your system. Also what brand is your hedgehog (Resistor) ? The chinese ones are crap.

arnaudov

The resistor (hedgehog) is removed from W219 original working. At one time I replaced my fan with the hedgehog I bought, or the new fan with my hedgehog, but it kept doing the same numbers. I finally got my fan and my hedgehog back. Regarding the sensors that the colleague mentioned above, how can I measure them? When I went to the STAR diagnostics, they looked at everything 3 times, read the whole car and finally they told me somewhere something breaks the tires, the CAN communication stops. And no one wants to bother to fix the car anymore I don't know what to do..

nd-photo.nl

-the ambient temperature sensor > should be seen in dashboard

-temp sensor under the steering wheel > somewhere in star



-temp sensor in the overhead control panel > somewhere in star



-temp sensor in blower housing (also accessible under steering wheel) > not sure, but I expect star

I have an Autel, so things might be a bit different. I found out by scanning/looking at values that 2 interior temp sensors were broken. I replaced both of them. More pictures in my build thread (see first post for index) > https://mbworld.org/forums/c219/8443...ld-thread.html

arnaudov

Thanks for the useful information! I'll try to take them apart this weekend. Am I understanding the sensor locations correctly:
Should there be one sensor under the steering wheel? Where you put the key there is something like a small round net behind it is this sensor?
Should there be another sensor up in the ceiling? Where are the interior lights and the sunroof button?
And where can I find a third sensor? You wrote again under the steering wheel near the radiator fan, but the fan is at the passenger seat? Is there supposed to be a sensor under the glove box of some kind somewhere around it?

And all these problems I'm having, could it be from one of these sensors? How would you advise me to measure them to see if they work? Is it possible with a multimeter or should I just look for new ones to replace them?

Thanks in advance! If you happen to be able to tell me with video material or photos of any of the sensors and how exactly the panels are disassembled to get to them, I would be grateful!

nd-photo.nl

Should there be one sensor under the steering wheel? Where you put the key there is something like a small round net behind it is this sensor?
Yes 100% correct! Its a bit hard to get to, but I only removed the cover panel to gain access. To remove the sensor, turn it and then pull it back. The electrical plug is removed easily

Should there be another sensor up in the ceiling? Where are the interior lights and the sunroof button?
Yes, 100% correct. The overhead control panel also has a small round net, the sensor is behind it. Read the post in my build thread, the hardest part is getting the rearview mirror back in place

And where can I find a third sensor? You wrote again under the steering wheel near the radiator fan, but the fan is at the passenger seat? Is there supposed to be a sensor under the glove box of some kind somewhere around it?
Its on the driver side, close to the gaspedal. See movieclip below, its from a S-class but the position is the same

You Tube

And all these problems I'm having, could it be from one of these sensors?
They have some relation with how hard the fan should be blowing.

How would you advise me to measure them to see if they work?
What value they give back should be visible in STAR

Is it possible with a multimeter or should I just look for new ones to replace them?
I would replace them if they never have been replaced, they are note that expensive. The one in the overhead control panel is a simple thermistor which can be replaced with some basic soldering skills.

nd-photo.nl

Might also be valuable: https://www.pelicanparts.com/techart...or_Testing.htm

Might also be something with the control panel

rodneypierce

I'm willing to bet it's the resistor. The"hedgehog" as you called it. This is 100% the symptoms of a bad blower motor resistor.

arnaudov

Hello, everyone! Thanks to the colleagues who responded, I did some tests and I want to say what I found out so far.
I took apart the covers under the glove box to get to the fan and resistor.
I looked at the measurements that nd-photo.nl published and decided to do them myself with a multimeter.
I also watched this clip.

I noticed that there is always constant current in the socket that is connected to the resistor and the 4th pin. Even without the car in contact, when I make measurements between the 2 thick wires, the red and the brown, there are 12 volts. If I start the car it goes up to 13-14.
If I put a minute on the multimeter on the minus of the socket and check with the other end the thinner wires there are also currents and different voltages.
Now the most interesting part: Measured and I see that there is current in the socket that enters the resistor, I plug this socket into the resistor and measured with a multimeter the other socket with 2 pins where the fan is connected and there is no current.
Neither with contact nor with the engine saved, voltage enters the resistor itself, but there is no power in the socket that turns on the fan. 0 volts I change the needles of the multimeter on the different 2 pins there is no power. And therefore there is no heating or air conditioning. It comes and starts blowing from rain to wind. Especially when the car is warmed up to 90 degrees and I drive it outside the city for about 30-40 minutes, then the heater usually comes on and starts blowing.

Is the hedgehog/resistor the problem?
Because as I mentioned in the topic, sometimes as it works and blows cold from the air conditioner, it suddenly starts blowing warm at a high level.
Could all these problems be from this resistor?
As I mentioned in the topic some time ago, I had bought a second-hand resistor and a fan, but the problem remained and I still had no heat, it worked when it wanted.
What is the chance that both of them had such a failure and what would you advise me to buy a new resistor or how can I be sure that the problem is with it?

I think that if there is no current in the output pins for the fan, then the problem is with it?

arnaudov

Hello, I solved the problem, it turned out that the rheotana/stove I have does the trick.
After they disassembled the whole car to look for where the communication breaks, it was found that the problem is in the stove in question. When it is turned off, everything starts working normally and does not stop.щ
I leave it off because a brand new stove costs a lot of money and the labor will be even more expensive.
I'm waiting for my car to be assembled and I'll pick it up. All this cost me 5 days at the repair shop and $400.
At first there were doubts that the problem was caused by a motor on a valve that shorted, but it turned out that they function well and the problem is in the stove.
I also had a problem, which is that in the summer, when I turned on the air conditioner on cold, the jet was very weak and did not cool well. It turned out that the problem is in some screws that are on the compressor. Will trade for about $150. And everything should be fine.