Hey guys,
I have a rather unusual problem, that I have searched for not only here but another slk forum and have found a thread or two with the same symptoms but they were never finalized nor was anyone able to figure out what is causing this. So I am creating this thread so once I find the issue that is causing this I will post the answer in here clearly and yes I will find the problem hehe.
So a few months back my radiator fan quit working completely and the low coolant light turned on. Straight away I knew the issue was the Fan Control Module which I ordered brand new from AutoHausAz and replaced it.
The Radiator fan sprang back to life straight away and everything worked fine for a month or so. I just recently had MB replace a bunch of parts under warranty for the leaky cam solenoid to include a brand new ECU.
But right before I turned my car to them, I noticed my temps reaching 80c and realized that the radiator fan is not working again, at first I though no way my control module quit working again but I quickly figured out that is not the issue.
So trying a few things and like mentioned above doing some searching I have noticed that the fan does turn on weakly when the AC or heating is set to full(Defrost) like mentioned in the threads I found in the search.
I have read several threads about the notorious K40 relay and have not check it out yet as I just got the car back today, but no one in the sticky thread about has any of the symptoms I am having and I am not having any of the symptoms they are having, although I should probably look into replacing it anyways as the car has 109k miles on it already.
So I started searching and I have found a few threads with the same exact symptoms I am having but as mentioned above all the threads would just end in a dead end. Symptoms being Fan turning on weakly when full AC or Heater Defrost is turned on.
Anyways tomorrow I will check my K40 relay regardless and also provide direct power to my fan to rule out a bad fan or bearings.
Any insight would be greatly appreciated to help me diagnose this issue.
Thank you,
Mike
I have a rather unusual problem, that I have searched for not only here but another slk forum and have found a thread or two with the same symptoms but they were never finalized nor was anyone able to figure out what is causing this. So I am creating this thread so once I find the issue that is causing this I will post the answer in here clearly and yes I will find the problem hehe.
So a few months back my radiator fan quit working completely and the low coolant light turned on. Straight away I knew the issue was the Fan Control Module which I ordered brand new from AutoHausAz and replaced it.
The Radiator fan sprang back to life straight away and everything worked fine for a month or so. I just recently had MB replace a bunch of parts under warranty for the leaky cam solenoid to include a brand new ECU.
But right before I turned my car to them, I noticed my temps reaching 80c and realized that the radiator fan is not working again, at first I though no way my control module quit working again but I quickly figured out that is not the issue.
So trying a few things and like mentioned above doing some searching I have noticed that the fan does turn on weakly when the AC or heating is set to full(Defrost) like mentioned in the threads I found in the search.
I have read several threads about the notorious K40 relay and have not check it out yet as I just got the car back today, but no one in the sticky thread about has any of the symptoms I am having and I am not having any of the symptoms they are having, although I should probably look into replacing it anyways as the car has 109k miles on it already.
So I started searching and I have found a few threads with the same exact symptoms I am having but as mentioned above all the threads would just end in a dead end. Symptoms being Fan turning on weakly when full AC or Heater Defrost is turned on.
Anyways tomorrow I will check my K40 relay regardless and also provide direct power to my fan to rule out a bad fan or bearings.
Any insight would be greatly appreciated to help me diagnose this issue.
Thank you,
Mike