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the fan runs based on coolant temperature and pressure in the ac system then based on a variable speed controller internal to the fan.
it has constant voltage so correcting voltage wont help, and this has nothing to do with the resistor you replaced.
most likely one of the two sensors (pressure and temp) is sending the wrong signal causing the car's computer to trigger high speed fan running all of the time, however, there is a slight chance the issue is also internal to the fan's speed controller.
the cause can be verified with a factory BMW scan tool which can monitor all inputs and outputs from all systems. I assume this this testing has not been carried out.
if you would like to avoid guesswork on this, you will need to invest in this type of diagnostic
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Hi steve can I sort this out myself?? can I repair the two sensors (pressure and Temp)? when can I find the speed controller?
Please do not forget to CLICK ON a positive rating as this is the only way I receive credit for my answer, thank you
if you want to avoid guesswork, the proper diagnostics with proper equipment must first be carried out
if you want to start replacing sensors without first verifying, you could potentially do this yourself, but I can't say for sure as I do not know your abilities and equipmpent level
the speed controller is internal to the fan, it is not something you can find seperately/
Hi steve sorry about the wait, ok where are these sensors?
the temp sensors is in the radiator/outlet hose
the pressure sesnsor is at the drying container of the AC system