E90 climate control fan follows engine RPM

Jelle458 · 06-23-2022, 07:08 AM

After owning my E90 330i for some time now a new sound started to appear.
I was scared it was engine related, as the sound pitched up or down in corrolation to engine RPM, but when I exited the car and opened the engine bay everything sounded just fine.

I found out the noise went away when I turned off the fan for the climate control.
If I turn it up, I still have the changing noise that follows engine RPM, just a bit higher pitched.
I always drive with the fan at lowest possible setting though, as I find anything else extremely windy inside the car. I even turned it almost all the way to the windshield, to get as little out the air ducts as possible.
If I turn the fan speed to max I don't have this noise.
Possibly the fan is receiving more voltage the higher RPM on the engine, which is very weird to me.
I didn't change anything on the car, while I have owned it I only changed out the stereo and headlights, but this came out of the blue, not at the same time as something was changed.

Does anyone know of this? It is actually pretty annoying, as it is pretty loud. I need to turn the speakers almost to maximum not to hear it, and then I can't hear anything but music.

ctuna · 06-23-2022, 02:13 PM

Don't know about Euro Cars but you should measure the output of your
Alternator to see if it is regulating the voltage correctly.
In the US there have been a number recalls relating to the wiring for the
Heater/Blower due to defective wiring.

Jelle458 · 06-27-2022, 07:57 AM

Quote:

Originally Posted by ctuna

Don't know about Euro Cars but you should measure the output of your
Alternator to see if it is regulating the voltage correctly.
In the US there have been a number recalls relating to the wiring for the
Heater/Blower due to defective wiring.

Thanks for the answer ctuna, can always count on you knowing something

Does a 12V cigarette measure thingy work well here? I have one that I bought randomly, shows on most cars 14V when car is started, and 12V when car is turned off, and I've used this in the past to check if alternator works.

The poles on the generator isn't exactly easy to get to but if I have to I have to

:

ctuna · 06-28-2022, 08:58 AM

Unless the thingy you are talking about measures the voltage as well
as a normal voltmeter it may not update fast enough to tell you much.

Easy enough to change the fan is the voltage is stable.
There is a recall for fan wiring.

06-23-2022, 07:08 AM	#1
Jelle458 New Member 12 Rep 29 Posts Drives: 330i E90 Join Date: Aug 2021 Location: Denmark iTrader: (0)	E90 climate control fan follows engine RPM After owning my E90 330i for some time now a new sound started to appear. I was scared it was engine related, as the sound pitched up or down in corrolation to engine RPM, but when I exited the car and opened the engine bay everything sounded just fine. I found out the noise went away when I turned off the fan for the climate control. If I turn it up, I still have the changing noise that follows engine RPM, just a bit higher pitched. I always drive with the fan at lowest possible setting though, as I find anything else extremely windy inside the car. I even turned it almost all the way to the windshield, to get as little out the air ducts as possible. If I turn the fan speed to max I don't have this noise. Possibly the fan is receiving more voltage the higher RPM on the engine, which is very weird to me. I didn't change anything on the car, while I have owned it I only changed out the stereo and headlights, but this came out of the blue, not at the same time as something was changed. Does anyone know of this? It is actually pretty annoying, as it is pretty loud. I need to turn the speakers almost to maximum not to hear it, and then I can't hear anything but music.
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06-23-2022, 02:13 PM	#2
ctuna Lieutenant General 1911 Rep 13,102 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	Don't know about Euro Cars but you should measure the output of your Alternator to see if it is regulating the voltage correctly. In the US there have been a number recalls relating to the wiring for the Heater/Blower due to defective wiring.
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06-28-2022, 08:58 AM	#4
ctuna Lieutenant General 1911 Rep 13,102 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	Unless the thingy you are talking about measures the voltage as well as a normal voltmeter it may not update fast enough to tell you much. Easy enough to change the fan is the voltage is stable. There is a recall for fan wiring.
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