Fixed the Buzzing Noise in my Dash!!!!! (HVAC Sampling Fan cleaning - No pics)

[Busta]

Thanks for the link qsilver. They also have another version of the same fix @ http://www.bimmerboard.com/forums/posts/204985

[bmw7833]

+1..Thkx for pic..

[bmw7833]

Try to DIY today, but still can not solve the problem, still have the buzzing sound from HVAC..Now planning to take out the fan from the HVAC..Can i just use the HVAC without the fan thingy??

[Busta]

I had the same problem. I tried this fix but the fan itself was creating a noise after cleaning. I removed the fan, I do not use the AUTO feature which this fan is used for..so I should be ok. I'll try to find a new fan in the future.

I think you'll be ok if you remove it and do not use the AUTO feature.

My buzzing is gone

[bmw7833]

Yes, me too..After cleaning the fan still get the buzzing..Actually what's the fan use for?? Jus for AUTO feature??

[Alpina540i]

I cleaned my fan and it still made noise ! I don't want to remove it so I am going to try to oil the shaft the motor spins on.

The fan draws interior air over a temp sensor I think.

[bmw7833]

So it is ok when i remove the fan if i use only manual setting??

[Busta]

Yes it is.

[Qsilver7]

Er, uh...the fan draws air into the HVAC unit where a thermostatic sensor determines what the air temperature is...this information is used regardless of the system being set on AUTO.

The temp sensor in the HVAC unit is used to keep the air temperature that is set by YOU, the driver. The AUTO programming operates the stepper motors and automatically chooses the AIR DIRECTION (windshield/dash/floor) and the FAN SPEED (if you have AUTO set on above the fan speed dashes). If you had the regular IHKR HVAC system, the temperature would be regulated by the position of the temp dial and how far you've turned the bowden cable. The AUTO IHKA system...you have a digital thermostat and the temp is determined by the thermostatic sensor which uses the fan to draw in air from the cabin.

The temperature that is selected by the driver or passenger...is regulated by the HVAC unit knowing what the temperature inside the cabin is. If you have your TEMP set at 70 degrees (F)....how do you think the HVAC system regulates and keeps the car at the temp? The HVAC unit uses the info from the thermostatic sensor that the little fan draws in thru the vents in the front of the control unit.

Removing the fan probably doesn't create a serious problem...but the temperture regulation of the cabin's air probably won't be as accurate as it could be.

(sorry if I'm repeating myself in this post...I'm sleepy but can't fall to sleep...not sure if I'm making sense or not)

[capn shawn]

Capn Shawn: just a comment (neither for/against, or negative/postive)

Removing the little fan thingy doesn't really change the fact that your HVAC system is automatic. I think you've only made the system a little less efficient rather than disable the "auto" function.

Think of the HVAC system in your home...the only difference being that it doesn't automatically close/open the heating registers (similar to the stepper motors opening/closing the flaps in the ducting). But let's say your home's HVAC system had a little fan on the thermostat that drew air in from the room it was located to track the rise/fall of the air temperature in the house...which corresponds to it turning the HVAC system on to either maintain consistent heating/cooling of your home.

Granted, most home HVAC systems also have a control that can turn the fan on (remove it from auto mode etc). I think all you've done by removing the fan is remove the HVAC system's ability to fine tune the accuracy of the air's temperature inside the cabin.

The AUTO and Air Direction buttons on your car's HVAC system allows you to choose between auto mode and manually selecting air direction...you can also stop the fan blower from automatically adjusting (auto fan feature is activated when AUTO appears above the fan speed dashes in the display).
***********************************
***********************************
As far as pictures...since the e39, e38, and e46 were built during the same time...many components are very similar. Sometimes you can check their forums for help too...in this case the e38 auto HVAC control unit is VERY similar to the e39. The button layouts are slightly different but the little fan thingy and the way it draws cabin air in across the temp sensor is basically the same. Hopefully this link will be helpful to you e39 owners : http://www.bimmerboard.com/forums/posts/428942/

Here's a teaser pic from the link above: (btw, when I opened my 97's HVAC unit...the dust was unbelievable...the image below looks CLEAN compared to what mine looked like!)

Don't take offense... I know what a thermostat does. I was an engineer for White Rodgers, a major thermostat manufaturer, for 5 years. What I did by removing the fan is to remove the stupid noise in my dash. I realize how moving the air over the thermistor/RTD/thermocouple dramatically changes the PID parameters of the HVAC system. I'd rather have a system that overshoots the setpoint a bit than one that pisses me off every time I get in the car. When I get too hot, I turn the temp down manually... it really isn't that hard.

[Qsilver7]

Removing the fan probably doesn't create a serious problem...but the temperture regulation of the cabin's air probably won't be as accurate as it could be.

Don't take offense... I know what a thermostat does. I was an engineer for White Rodgers, a major thermostat manufaturer, for 5 years ... I realize how moving the air over the thermistor/RTD/thermocouple dramatically changes the PID parameters of the HVAC system.

I'd rather have a system that overshoots the setpoint a bit than one that pisses me off every time I get in the car. When I get too hot, I turn the temp down manually... it really isn't that hard.

No offense taken at all. In fact, I appreciate your description which uses more "technical terminology" (and crystallizes my concerns & essense of what I was trying to say) of what happens when the fan is removed...and the affect it will have on the "PID parameters of the HVAC system".

Your input will be helpful to those that removed theirs to know that more "manual" manipulation of the system may be required.

Again, I appreciate the "technical" info you brought to the discussion.

[andreslara]

Works really good for my E39 2002, thanks !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Ix540xI]

can you repost the picture, i cannot see the pics

[Wolfen]

i put a powerful vacuum on each little fan opening. It sucked all the dust bunnies into the screen. Then with a toothpick i plucked all the dust bunnies out. There was plenty. Redid it again and then blew shots of compressed air into each little rib moving it back and forth. All Done.

I got this idea because of the buzzing noise also. I noticed dirt inside the little ribs.

[Qsilver7]

can you repost the picture, i cannot see the pics

The original poster's pics have been gone for a LONG time (orig post was in Nov/2006)...which is why I linked to a write up with pics in post #25. There are links in posts #25, #26, and #35 that shows pics of the small wheel and instructions on how to open up the HVAC unit.

Don't be thrown off by the units coming from the e38...the HVAC control units are pretty similar in design...seeing how the one is deconstructed etc...is pretty much how the other one is done.

[webdesigner]

Wow, is this what it is?

I would just hit my dash and make it go away

[jamesdc4]

can you repost the picture, i cannot see the pics

The original poster's pics have been gone for a LONG time (orig post was in Nov/2006)...which is why I linked to a write up with pics in post #25. There are links in posts #25, #26, and #35 that shows pics of the small wheel and instructions on how to open up the HVAC unit.

Don't be thrown off by the units coming from the e38...the HVAC control units are pretty similar in design...seeing how the one is deconstructed etc...is pretty much how the other one is done.

I've PMed the OP about the broken photo links. He hasn't posted since 2007, but has been lurking recently (7/09). Hopefully he will be able to fix the photos so we can see this on an E39.

[morcre]

Great to know what was causing the noise. I had a look at the link in the OP and the '97 E38 setup is certainly a lot different to my Jan '98 E39.

I'm not sure if mine had been cleaned previously as there wasn't as much dust and gunk as I'd thought there would be for a car nearly 12 years old.

I am not the best at DIY or the most patient person, but found this very straightforward to do. Now it is silent, I had to check a couple of times to make sure something was happening!

Thanks to the OP and the link on bimmerfest for making it that much easier!

[Kevin Da Clean1]

More great info from you guys... !

[cnn]

Before you guys laugh, I was too tired (and maybe lazy LOL....), so this is what I did:
- I used an electric Leaf Blower (the blower you use to blow leaves out of the driveway).
- Aim the Leaf Blower at either horizontal louvers on either side of the HVAC buttons.
- 5 seconds on each side, all the lints fly away!!!

It is short and sweet and nothing to worry about! LOL...

[newbmwownr]

Wow, is this what it is?

I would just hit my dash and make it go away

bahahaha. i freaked the first time heard it. then i started pushing every button on the dashboard. then i upgraded to hitting the darn thing. hahaha

Before you guys laugh, I was too tired (and maybe lazy LOL....), so this is what I did:
- I used an electric Leaf Blower (the blower you use to blow leaves out of the driveway).
- Aim the Leaf Blower at either horizontal louvers on either side of the HVAC buttons.
- 5 seconds on each side, all the lints fly away!!!

It is short and sweet and nothing to worry about! LOL...

this is what i had in mind after first reading all the technical stuff people did. i thought to myself, "why not just blow on it?" lol

[shifta]

I pulled mine out and cleaned it thoroughly, put it all back together in the correct manner and plugged everything back in, but now the bloody HVAC system is always on at 24 degrees celcius and full fan speed!!! none of the buttons work at all, plus the fan is really noisy, i did everything very carefully and in the right way. But nothings working!! HELP!!! does it need resetting or something??

[IRUNEDM]

so thats what the noise is. it was starting to bug me. guess i have got a diy to do this weekend

[cnn]

I took some pics:

- Torx #10 or Allen 1.5mm counter clockwise to remove MID
- Reach your hand behind to push the HVAC Panel outward (held by 2 side tabs)
- I inspect my HVAC Sampling Fan by tilting the HVAC Panel downward.
- HVAC Sampling Fan looked clean so I did not bother cleaning it.
- But if you want to clean the Sampling fan, it is easy, undo the connectors and remove the HVAC Panel and bring it to your kitchen table for a good clean-up.

[Dolby Loy]

Thanks all experts here....HK$20 for the 3in1 and the noise gone with the wind!


Uploaded with ImageShack.us