W209 Cooling fan stuck at 40%
07-27-2022, 06:04 PM
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CLK320
W209 Cooling fan stuck at 40%
Hello all,
2003 CLK320 A/C is blowing warm at stops, found the pressure/temp sensor would read up to 24bar with the A/C module only requesting 40% duty cycle on the cooling fan. I can perform an actuation test with the scan tool and the cooling fan will respond correctly with it going from 50% - 90% just fine. If I remember correctly pressures between 14bar and 20bar should be around 100% duty cycle. I'm leaning towards replacing the A/C control module, however I know the Front SAM is the main operator of the cooling fan. Has anyone run into this before? Any help is appreciated, thank you!
2003 CLK320 A/C is blowing warm at stops, found the pressure/temp sensor would read up to 24bar with the A/C module only requesting 40% duty cycle on the cooling fan. I can perform an actuation test with the scan tool and the cooling fan will respond correctly with it going from 50% - 90% just fine. If I remember correctly pressures between 14bar and 20bar should be around 100% duty cycle. I'm leaning towards replacing the A/C control module, however I know the Front SAM is the main operator of the cooling fan. Has anyone run into this before? Any help is appreciated, thank you!
07-30-2022, 06:41 PM
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MY'14 W212 M276 3.5NA @60kMi
crazy fan --> Over charged!
Hello all,
2003 CLK320 A/C is blowing warm at stops, found the pressure/temp sensor would read up to 24bar with the A/C module only requesting 40% duty cycle on the cooling fan.
I can perform an actuation test with the scan tool and the cooling fan will respond correctly with it going from 50% - 90% just fine.
If I remember correctly pressures between 14bar and 20bar should be around 100% duty cycle. I'm leaning towards replacing the A/C control module, however I know the Front SAM is the main operator of the cooling fan.
Has anyone run into this before? Any help is appreciated, thank you!
2003 CLK320 A/C is blowing warm at stops, found the pressure/temp sensor would read up to 24bar with the A/C module only requesting 40% duty cycle on the cooling fan.
I can perform an actuation test with the scan tool and the cooling fan will respond correctly with it going from 50% - 90% just fine.
If I remember correctly pressures between 14bar and 20bar should be around 100% duty cycle. I'm leaning towards replacing the A/C control module, however I know the Front SAM is the main operator of the cooling fan.
Has anyone run into this before? Any help is appreciated, thank you!
24Bar is 350PSI.... somebody way over charged your A/C system.
Make use of a pressure gauge-set to measure system Lo/High side load (never mind using a weight scale).
When the circuit is overloaded the compressor has no headroom to create high/low side pressure to circulate the refrigerant.
Get your pressure back down inline... then expect the fan speed to normalize with good A/C temperatures.
🤘
Last edited by CaliBenzDriver; 07-30-2022 at 07:33 PM.
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