Radiator Fan Woes (cannot fix it)
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W204 350 CDI D6
Radiator Fan Woes (cannot fix it)
I am hoping someone can help me here, i have a issue with the Aux fan on my 2010 W204 350cdi.
The fan comes on randomly when the ignition is off and drains the battery overnight. If i leave my keys in and the ignition on its fine it seems to occur when the can bus goes to sleep.
So far i have done the following.
None of the above has sorted it, as soon as you plug in my scanner the fan stops as it requires the ignition to be on, i have no fault codes, star is not reading any abnormal requests for the fan to turn on.
The odd part is if i disconnect the fan and drive the car it smokes like a steam train, plug the fan back in and its golden, i get no power issues or problems when driving it, its fine.
I am now at a point of replacing the F-Sam and Motor ECU as nothing else requests the fan to operate, when i check the reference voltages to the fan when the car is off it looks fine the majority of the time, however, i did watch the request signal fluctuate at one point which seems to be when the fan starts and stops randomly, hence now looking at the Motor ECU. .
If anyone has any ideas i would really appreciate it, i am currently haemorrhaging money into it , but with no fault codes, shorts or corrosion i can see other than throw parts at it i am at a loss.
Thanks to all in advance
The fan comes on randomly when the ignition is off and drains the battery overnight. If i leave my keys in and the ignition on its fine it seems to occur when the can bus goes to sleep.
So far i have done the following.
- Fit new AC pressure sensor and updated HVAC software
- Replaced the Fan with the updated pert as per the MB Bulletin
- Checked the F-Sam for moisture ingress
- Checked the wiring for shorts
- Replaced the water temp sensor
- Removed all after-market audio kit
- Checked Fan plug for corrosion
- Checked ME ECU for corrosion or moisture on the plugs
None of the above has sorted it, as soon as you plug in my scanner the fan stops as it requires the ignition to be on, i have no fault codes, star is not reading any abnormal requests for the fan to turn on.
The odd part is if i disconnect the fan and drive the car it smokes like a steam train, plug the fan back in and its golden, i get no power issues or problems when driving it, its fine.
I am now at a point of replacing the F-Sam and Motor ECU as nothing else requests the fan to operate, when i check the reference voltages to the fan when the car is off it looks fine the majority of the time, however, i did watch the request signal fluctuate at one point which seems to be when the fan starts and stops randomly, hence now looking at the Motor ECU. .
If anyone has any ideas i would really appreciate it, i am currently haemorrhaging money into it , but with no fault codes, shorts or corrosion i can see other than throw parts at it i am at a loss.
Thanks to all in advance
