Air blower noise from Air-Cond Control Panel

[supersub]

Hello masters & sifus out there,I have noticed a soft blower sound coming from the the two vent slots (left & right side) of the Air-Cond Control Panel. The vent slots are the ones just below the temperature adjustment controls. The blower sound is still there even after the engine have been switched OFF.The next morning when I get into the car, even before starting the engine, I can still hear that blower sound running. Anybody with similar experience? Can someone please help how to stop it.:smokinlease note: It is not the parking vent fan. The parking vent fan is loud and the air comes out from the air-cond vents.BTW, it's a E39, 525i

 

[bimmerholic]

It's your HVAC Sampling Fan that's making that buzzing noise.
It makes that buzzing sound when it there's a lot of dust around it. What you need to do is, remove your HVAC (a/c controller unit) and open it up, locate the fan, clean it, oil it at the shaft...and you're good to go.

Cleaned mine twice. Reason why even before starting the car, you hear it is because when you unlock the car, the HVAC is armed. Just like the orange light next to "P" on your gear lever.

Here's the DIY write-up: http://www.bimmerboard.com/forums/posts/428942/
Easy.

 

[supersub]

Bimmerholic, thanks for the great piece of info:rock:

Will try it out and post the results once done.

 

[supersub]

Yes, it worked.

I had the magnetic air sampling fan out. The fan was covered with dust. Had it cleaned then, added a small drop of WD 40 to the shaft before putting it back. Viola, the sound has disappeared.

Thanks again to bro Bimmerholic for the useful post

 

[bmw7833]

Ahahh, i took out mine and throw away the small fan thingy. Problem settle!

 

[supersub]

Bro bmw7833, right if the blower sound comes back I may decide to junk it also. As I understand it, it is to sample the cabin air temperature ( for displaying the cabin temperature only) So no major function.

Any comments from the other sifus out there.....?

 

[alantiong]

supersub.. it does much more than that. it picks up the temperature in the cabin and this is essential to compare with external temperature to balance the load of cooling on the compressor and the condenser fan. . so its much more complicated than you think. my advice.. keep it and save yourself some headache.

 

[rpmnut]

Everything on the car serves a purpose, I always say. If the car didn't need it to work properly they wouldn't have put it in...

The sampling fan draws air in from the cabin into the HVAC electronics so cabin temp can be established. Without the fan, the sensors in the HVAC unit will run warm constantly, forcing the system to over-compensate for what it thinks is high cabin temp.

Long term, this will tax your air cond compressor and increase your fuel consumption....

 

[bmw7833]

What to do, the buzzing sound is really suck!

 

[bimmerholic]

What to do, the buzzing sound is really suck!

simple take it out and clean it bro. problem solved.

 

[bimmerholic]

There's a reason why it's called the "sampling fan". else it wouldn't be called sampling.or just simply fan.

 

[bmw7833]

Mine one can not solve la, the buzzing sound still there and decide to throw it away after 3 times i clean it.

 

[rpmnut]

Did you try lubricating the motor spindle with some wd-40 first before throwing away the fan?

 

[moots]

the sampling fan on mine wasn't irritatingly noisy but it can be heard spinning when i close the door before engine start(you know how quiet our e39 cabin is, such that you can hear the sound of silence).but i took mine apart anyways to clean out all the dust and lubricated the fan shaft ever so lightly with light grease(in can) and reassembled....... WOW!I now CANNOT hear that feller spin ANYMORE.I thought alamak koyak oledi....i must have buggered something up.so I removed the module from the center console and had a look at the back and true enuff........... the fan was spinning...........SMOOTHLY.............

you guys with noisy sampling fan.....u know what you have to do now don't you....

 

[supersub]

alamak, the fan buzzing sound is back.

As Moots pointed out, will need to dismantle the fan and clean it properly and add some grease to the shaft before re-assembling it. I agree with bmw7833 the noise damn irritating especially early morning when you step into the cabin before even starting the engine you hear something buzzing away....

 

[supersub]

Hi, back to report the status.

Moots, you are absolutely correct. If you do it properly the buzzing sound will be solved. The way to do it is to put some light grease on the spindle/shaft.

Finally killed that irritating "buzzing" sound.

Bro bmw7833, need to be patient.... try applying some light grease on the spindle/shaft... it should solve the squeaking/buzzing sound.

 

[moots]

bro supersub,unfortunately the noise came back after 2 days.so i opened it up again,cleaned the shaft and this time put a dab of new semi syn engine oil and it has been quiet since.