There is a sound in my dash that is coming from the drivers side vent that is in the middle of the ac head unit where a temp sensor would be. I took the car to a dealer who changed out the Final stage unit and said that would take care of the resistor which was supposedly making the noise. Well, it did not fix the problem. The car be turned off or on and there is a constant noise sound of a small fan running. Both AC and heater work as normal. Any ideas??? Thank you in advance!!
shell5329
There is a small fan inside the HVAC control panel which draws cabin air into the left slotted area on the control panel. This is to measure cabin air temperature.
As soon as you open the door, or unlock the car, the fan starts, and shuts off 16 min after exiting. Some make more noise than others; with my old ears, I can just barely hear mine in a quiet garage.
As soon as you open the door, or unlock the car, the fan starts, and shuts off 16 min after exiting. Some make more noise than others; with my old ears, I can just barely hear mine in a quiet garage.
i have the same problem with my car its only happened now that it is the winter is i normall for it to do that or not. i have replaced the final stage resistor a few years ago. i dont want to change that now that i have read this post it does only come on when i open the doors with the remote or of im just sitting in the car and i use any electical item in the car will it drain my battery ive just brought a new bosch one
please help
please help
shell5329,
Don't know the official name of the fan, but let's call it the cabin air sampling fan, because that's what it does.
Some make more noise than others, due to dust or soot (from cigarette smoke) on the blades. The panel can be removed by first removing the cup holders, and pushing the panel out. The fan can then be cleaned.
qwerty786,
If your heater blower is running when the ignition is off, the final stage unit is bad. There is a new style FSR available, that has about 3X the number of spikes as the old style.
Don't know the official name of the fan, but let's call it the cabin air sampling fan, because that's what it does.
Some make more noise than others, due to dust or soot (from cigarette smoke) on the blades. The panel can be removed by first removing the cup holders, and pushing the panel out. The fan can then be cleaned.
qwerty786,
If your heater blower is running when the ignition is off, the final stage unit is bad. There is a new style FSR available, that has about 3X the number of spikes as the old style.
Heating/AC fan is draining battery
My mechanic just determined after several attempts that a small fan in my dash continues to run intermittently while the car is parked and turned off. He has removed all fuses, etc. and still can't get the fan to stop running. It runs very slow but enough to kill a NEW battery overnight.
Is there an inexpensive fix to this? My mechanic is recommending getting rid of the car. 2000 BMW 540i w/135k miles......with other electrical problems like the ABS computer is bad, etc. Not real happy with the car.
My mechanic just determined after several attempts that a small fan in my dash continues to run intermittently while the car is parked and turned off. He has removed all fuses, etc. and still can't get the fan to stop running. It runs very slow but enough to kill a NEW battery overnight.
Is there an inexpensive fix to this? My mechanic is recommending getting rid of the car. 2000 BMW 540i w/135k miles......with other electrical problems like the ABS computer is bad, etc. Not real happy with the car.
I don't know that a new battery should die overnight due to the fan running.
Nothing springs to mind for the IHKA fan, besides replacing the unit. I'm sure there's a way to fix it more cheaply.
The ABS computer does not necessarily need to be replaced outright. You can have it repaired for a fraction of the price of a new one. EACTuning also has new computers for about $500.
Nothing springs to mind for the IHKA fan, besides replacing the unit. I'm sure there's a way to fix it more cheaply.
The ABS computer does not necessarily need to be replaced outright. You can have it repaired for a fraction of the price of a new one. EACTuning also has new computers for about $500.
Could be the blower regulator. http://www.bavauto.com has them. Just search on blower resistor.
IHKA -=automatic Heating and A/C There's also an IHKR (regulated Heating and A/C) system which is in the 2001 525i/iT that was imported to the USA and is available in other markets that uses rotory dials and bowden cables instead of electronic stepper motors to control the air flaps.
The little sampling fan inside the IHKA & IHKR panels isn't sold separately...so you won't be able to find it in the part database because it is part of the WHOLE climate control panel....it would be like trying to buy the chips on the internal circuit board. The fan thingy itself is not mechanical...it is initiated by a command from the GM (general module) to the IHKA panel...and it starts to turn.
And as stated...the little fan is sitting on a spindle inside the control panel and it slides right off when you open the control panel. It feels like it is held on by a magnet. Also..as previously stated...the fan does NOT run all night long. It is connected to the P-bus...which shuts down after 16 minutes of inactivity (after the car is shut down).
When the P-bus receives a signal from the door handles or the remote key...a signal is sent from the GM to items on the P-bus to WAKE_UP...one of those items is the sampling fan inside the IHKA panel...it begins to draw in cabin air across a small thermistor inside the IHKA panel.
If your HVAC systems FSU/FSR in the blower has failed...this is something totally different from the small little fan that we've been discussing that you can hear after the car is turned off.
If you are concerned about the little fan inside the IHKA panel...next time you're in the car...remove the key and sit there for 16 minutes. Make sure you do not activate any door handles or the sunroof or windows...and when you see the little orange light go out next the the gear shift handle...the little fan should turn off as well. They both are connected to the P-bus.
Here's a pic of the little fan...the IHKA panel has already been opened & the circuit board removed...you can see in the 2nd pic how the fan can be lifted right off it's little spindle...it is not held on the spindle by anything visible...that is why I assume that there some type of magnet...again, it slides right off the spindle with no problem:
The little sampling fan inside the IHKA & IHKR panels isn't sold separately...so you won't be able to find it in the part database because it is part of the WHOLE climate control panel....it would be like trying to buy the chips on the internal circuit board. The fan thingy itself is not mechanical...it is initiated by a command from the GM (general module) to the IHKA panel...and it starts to turn.
And as stated...the little fan is sitting on a spindle inside the control panel and it slides right off when you open the control panel. It feels like it is held on by a magnet. Also..as previously stated...the fan does NOT run all night long. It is connected to the P-bus...which shuts down after 16 minutes of inactivity (after the car is shut down).
When the P-bus receives a signal from the door handles or the remote key...a signal is sent from the GM to items on the P-bus to WAKE_UP...one of those items is the sampling fan inside the IHKA panel...it begins to draw in cabin air across a small thermistor inside the IHKA panel.
If your HVAC systems FSU/FSR in the blower has failed...this is something totally different from the small little fan that we've been discussing that you can hear after the car is turned off.
If you are concerned about the little fan inside the IHKA panel...next time you're in the car...remove the key and sit there for 16 minutes. Make sure you do not activate any door handles or the sunroof or windows...and when you see the little orange light go out next the the gear shift handle...the little fan should turn off as well. They both are connected to the P-bus.
Here's a pic of the little fan...the IHKA panel has already been opened & the circuit board removed...you can see in the 2nd pic how the fan can be lifted right off it's little spindle...it is not held on the spindle by anything visible...that is why I assume that there some type of magnet...again, it slides right off the spindle with no problem:
Okay, I was wrong.
The fan is a weird animal. Another fine example of twisted German engineering. It's driverless - that is, it only has two windings and a magnetic sensor. The driver circuitry is on the circuit board itself.
I have not found a direct replacement for this abomination. So I just cleaned and lubricated mine (the bearing seems to be in good shape still).
![Image]()
![Image]()
The fan is a weird animal. Another fine example of twisted German engineering. It's driverless - that is, it only has two windings and a magnetic sensor. The driver circuitry is on the circuit board itself.
I have not found a direct replacement for this abomination. So I just cleaned and lubricated mine (the bearing seems to be in good shape still).
I believe this fan keeps running in my car indefinitely, draining the fuctioning battery fairly quickly. I sat in my car for around 30 minutes and I continued hearing what I believe to be is a noisy fan running in the dashboard. It's not very loud, and it's not the HVAC blower either (that functions normally). The replacement for this thing is around $1000 including the logic board that it's attached to. Can somebody post how I can take this part out and at least give it a nice cleaning before I spend that much money?
The post below by Gstob tells us the importance of the small sampling fan!
http://www.bimmerfest.com/forums/showthread.php?t=709746&page=2
http://www.bimmerfest.com/forums/showthread.php?t=709746&page=2
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