CDI control unit Electrical Fan
Hi, I want swap my visco fan to electrical engine/ac fan on g270 cdi year 2002. Electrical fan has 4 pins.
Pin 1 is +12V Battery prefuse
Pin 2 is earth
Pin 3 is ignition +12V
Pin 4 is PWM signal from cdi control module, but I dont know which pin it is? Any advice.
For example on petrol engines (g500/g55) it is connector 4 and pin 39.
Thanks for any tips.
Sorry, not clear on what you are asking:
a.) You have a G270 CDI with belt-driven fan and want to fit an electric fan like from a G400,
or
b.) you have another G and want to fit the electric fan From a G270 CDI?
If (a), you might find the ECU information from WIS.
This may help
http://forums.mercedesclub.org.uk/showthread.php?t=131500
You may need to re-code your air conditioning control unit to operate through the ECU and the new fan, if presently it has a separate electric fan.
Here's a 270 circuit diagramme for the radiator
The link I'd posted above is for a 270 CDi in an ML and it mentions the pin and wire colour for the fan PWM.
Sorry, but I don't understand this diagram. I cant see M4/7 (engine suction fan), cdi unit connectors pin out. Anyway thanks for your post.
Read this thread, all the way through. The information is there for a 270 CDi.
http://forums.mercedesclub.org.uk/showthread.php?t=131500
Thank you very much. This information is useful for me. Today I tried to connect to my CDI control module (connector 3 pin45) cable and all 3 other cables to right place but nothing happened. Fan running only on 100%. No PWN regulation even via diagnostic. May be my ECU is not equipped with this signal on that pin 45. :(
Unfortunately I don't have pinout diagram of cdi control unit. (A6121530879)
Thanks.
You may need to version-code your ECU to enable that feature. Apparently you do need to do this for the air-conditioning control unit.
The circuit diag I posted above is for a 270 cdi and it doesn't indicate the radiator fan (as you stated). Therefore, did any 270 have the PWM output that you are seeking? Maybe it's only the 400 that has it.
How about using a VS drive to control the speed manually or a set of ballast resistors.
ML-270 CDi has it - see link above
I know that no W463 2.7CDI had electrical fan. It had only visco clutch, but as I mentioned I want to convert mechanical clutch cooling to electrical because my engine is equipped with bigger turbo (from 320cdi) and remapped ecu so I need more efficient cooling. Today output is approximately 175kW.
2.7cdi engine in other models (c-class, e-class, ml-class) have electrical fan. I know that I can regulate fan rpm via external module.
My idea was to disable aux ac fans and let big electrical fan to cool engine and also climate.
May be that I have to find way how to enable PWM output from mentioned pin. I had opened CDI unit and it seems that pin 45 is connected to some circuit.
Thank you all for your ideas and help.
btw sorry for my poor english :(
Here's an extract from the circuit diag from the ML270 which confirms the above info. ECU connector 3 pin 45 white for PWM signal to rad fan. You'll need to get a circuit diag for a ML ECU which is probably very securely helld
Roly's info confirms the pins and wire colours. However, if you've tried this already and there is no PMW, then I suspect that this function will need to be enabled / coded with a STAR diagnostics machine. This is the case for the Aircon-controller, as in needs to use the new fan also for Aircon condenser cooling.
Next week I will have star diag C4 unit, so I will try to code CDI2 engine control module and climate control unit KLA. (enable pwm). But I don't know how to do it. Because when I tried to find this coding in xentry simulation for CDI 2 UNIT, there was no option to code M/4 suction fan or something like that. I don't how to (code) enable it. In climate control unit is also no option for electric fan variant coding only coding for countries (arctic or hot countries) and option to run fan all time on 20% basic ventilation.
I also have development data but unfortunately I don't understand it and there is also only few options.
I don't know about the ECU, but there is a thread below about someone who replaced the aircon control unit and then it would not operate the fan properly, until it was coded to use the engine's electric fan. So, at least that is possible:
'....I had a similar problem, my problem started with a dealership change of my climate control head unit. My car is a 2000 C280 with an electric cooling/engine fan only. When I would start my car the fan would come on and stay on high until the car was shut down regardless of temp. The dealership told me this was normal so I believed them for 3 years! Finally I researched and found out that the climate control head unit needs to be version coded correctly in order to operate the cooling system in your vehicle properly. There is a document that explains how to do this which I can forward you if you feel it is your situation...
Hello, I am new to the forum.
I want to do this modification on my 2002 G class 270 CDi. I have been investigating, and indeed the PWM output is through pin 45 connector 3, which I am very clear about, is how to activate PWM. I have tried similar programs from other ECUs, C270CDi, and with that ecu the speed regulation works, but the car does not go well with that DUMP.
Has anyone managed to activate it?
Thank you.
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Hi mate,
thank you very much for reply.
a) is correct!
Now my car is equipped with visco clutch fan and I want to fit electrical fan exactly like on 400CDI.
I cannot find wiring diagram of ECU in WIS with legend of connectors and pin description. Three cables are 100% same like on other models, but connection to control module is problem. As you know there are a lot of versions of units on various models (I am not sure if 400 CDI and 270 CDI has same pin position and function). I read two articles about that. In one of them it was connector 4 pin 39 and in second it was connector 3 pin 45. So now I dont know. Maybe I will have to try one by one :), but I am afraid to do not damage control module.
I found only this diagram for G400 CDI in attachment.
Anyway thanks again. If you have some idea,please let me know.