[jam2reggae]

On my 2007 GL450 X164, the radiator cooling fan works intermittently, and sometimes none at all. This causes the engine to overheat.
When I disconnected the fan assembly while the engine is running, then turn off the engine/ignition and reconnected the fan, it works at full high speed then retracted and shut off. However, at the time it came on, if I switched the engine/ignition and a/c on, the fan works perfectly if the engine and a/c remain on. It do not repeat if I turn off the engine and restart.
Whenever the cooling fan does not come on the a/c does not blow cold air. There are no fault codes shown when I ran a diagnostic. Can anyone help me to determine the cause of this problem? Has anyone experience and resolved similar issues?
During my research I came across similar issues caused by the a/c pressure sensor, fan module and, ECM, and coolant temperature sensor. The fan assembly is brand new - I changed it because I thought the original assembly was bad. I was wrong.
The vehicle is not throwing a fault code. I am confused and need help ASAP.

Thanks
Lanny

 

[Witek_M]

What are you using to scan vehicle? Have you looked at actual values for suction fan?

 

[jam2reggae]

I am using the DAS/Xentry tool. I will look at those values however I have actuate the suction fan under the AAC menu. and it came on based on the command. Where do you/what command menu is used to check the actual values for suction fan?

Thanks.

 

[Witek_M]

I am using the DAS/Xentry tool. I will look at those values however I have actuate the suction fan under the AAC menu. and it came on based on the command. Where do you/what command menu is used to check the actual values for suction fan?

Thanks.

What makes you think engine is overheating? What is actual temperature?
ECU controls fan function based on engine temperature and/or request from AAC.

Take a look at this thread.

Radiator fan won't work unless AC is turned on

Recently i noticed the engine temperature is above normal, and I determined that the fan will not work unless the AC is turned on, as soon as the AC is off, the fan shuts off too. any ideas on how to fix that? Car: 2001 S320

www.benzworld.org

 

[jam2reggae]

What makes you think engine is overheating? What is actual temperature?
ECU controls fan function based on engine temperature and/or request from AAC.

Take a look at this thread.

Radiator fan won't work unless AC is turned on

Recently i noticed the engine temperature is above normal, and I determined that the fan will not work unless the AC is turned on, as soon as the AC is off, the fan shuts off too. any ideas on how to fix that? Car: 2001 S320

www.benzworld.org

OK!
It is overheating because the temp gauge went over 125 degrees, with full dash went RED and told me "COOLANT TOO HOT SHUT OFF ENGINE TO AVOID DAMAGES". The fan never came on and the a/c went hot.

 

[Witek_M]

All diagnostic tools follow same path.
Vehicle selection > Control Modules >Drive >MExx > Actual Values > Fan.
Take screenshots.

 

[jam2reggae]

All diagnostic tools follow same path.
Vehicle selection > Control Modules >Drive >MExx > Actual Values > Fan.
Take screenshots.

Thank you!
Today was a good day and the fan and a/c works as it should. I was unable to replicate the events of 2 days ago where the SUV overheated when the cooling fan nor the a/c did not work.
Please see fault codes attached from that occurrence. Also please see the pictures of the reading from the fan when:
1. the engine is cold
2. a/c is on low
3. a/c is on high

Thanks

 

[jam2reggae]

All diagnostic tools follow same path.
Vehicle selection > Control Modules >Drive >MExx > Actual Values > Fan.
Take screenshots.

More pic.

Thanks

 

[Witek_M]

In Picture 5/12 effective fan ratio should be 70%. Higher of the two requests. It is 59.61%

Is this genuine MB fan assembly?

 

[jam2reggae]

In Picture 5/12 effective fan ratio should be 70%. Higher of the two requests. It is 59.61%

Is this genuine MB fan assembly?

Agreed.
Yes it is a MB OEM fan assembly.
Could the Freon level or a/c pressure valve be a factor?

 

[Witek_M]

OEM my ass! If you bought it from MB dealer is has 24 month warranty.
You are getting faults for fan controller and coolant temp sensor as a result.

 

[jam2reggae]

OEM my ass! If you bought it from MB dealer is has 24 month warranty.
You are getting faults for fan controller and coolant temp sensor as a result.

Could the refrigerant pressure be a factor? The spec sheet attached required > 12 Bar and per the diagnostic result, it is < 12 Bar. See attached.

Thanks

 

[jam2reggae]

OEM my ass! If you bought it from MB dealer is has 24 month warranty.
You are getting faults for fan controller and coolant temp sensor as a result.

Really strange indeed. We checked the live data and compared it with that of the old fan and it is the same. The last reading of 59.61% should be at least 70%. Now we believe it could be the coolant temperature sensor malfunctioning.

 

[jam2reggae]

Really strange indeed. We checked the live data and compared it with that of the old fan and it is the same. The last reading of 59.61% should be at least 70%. Now we believe it could be the coolant temperature sensor malfunctioning.

By the way, the old fan is the OEM that came with the SUV.

 

[Witek_M]

Really strange indeed. We checked the live data and compared it with that of the old fan and it is the same. The last reading of 59.61% should be at least 70%. Now we believe it could be the coolant temperature sensor malfunctioning.

If you suspect coolant temperature sensor. Let is sit overnight and take some readings from various temp sensors. They all should be about the same +/- 2C.

 

[jam2reggae]

If you suspect coolant temperature sensor. Let is sit overnight and take some readings from various temp sensors. They all should be about the same +/- 2C.

Problem solved - the pins on the engine connection were bad, resulting in non-continuous connectivity when plugged into the fan module. The dealer removed the bad pins, rewired the connector, and the fan has been working for the past six months without any issues.

Thanks,
Jam2reggae