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Simple Final stage resistor pack question

4K views 19 replies 7 participants last post by  ZeGerman 
#1 ·
Im getting no air whatsoever from my vents regardless of what settings are on my digital climate control unit. I have read contradicting information that says if you have air on High settings but no other settings than its the final stage unit. Then I have also read that If/when the final stage fails, it is possible to have NO AIR on any settings including high which is the symptom I am having. Just replaced my water pump, Tstat & housing, Heater blower motor and radiator as well as climate control computer. everything was working perfect for a few weeks then out of nowhere the air flow just stopped . its definitely electrical, thoughts?:mad:
 
#4 ·
If you have automatic climate control, it's called a final stage unit, and if it goes, you won't have air on any setting. If you have manual climate control (dials), it's called a blower resistor and the fan will bypass the resistor when set to high and blow air only on high. Replacing the FSU is sooo much easier than replacing the blower motor, which will make a squeaking / chirping sound as it starts to fail.
 
#5 ·
Blower motor was making chirping sound for months before it went and after isolating the circuit on 12v it wouldnt turn on and after we took it out the cages/fans were locked solid so it was definitely kaput. The climate control is digital in my car and thank you for clarifying about the difference in the operation of the FSU working on high when broken only for manual climate systems. Im fairly certain it is the FSU which hopefully will be here tomorrow. I have the old one out and ready to pop in the new one! Thanks again
 
#7 ·
had the mechanic do mine for me but there was a write up somewhere when I was checking around...
Someone posted a like on this forums to a site in bimmerforums i think with the writeup and pictures.
 
#8 ·
This one's the best:

http://www.dvatp.com/bmw/diy/hvac_blower/

I ended up doing it twice on my '06 328is 'cause the first used blower motor I got didn't work. If you buy a used blower motor, make sure you can get both squirrel cages off. It makes installation much easier. I'm assuming the brand new ones just twist right off, but used units are bit more difficult. You can twist them in opposite directions to loosen one of them, then I stood on a pair of channel lock pliers to clamp down on the hardened steel shaft and twist the second squirrel cage off. When you install the blower motor, you have to shift the cages back and forth to get the alignment within the airbox right. It's not a difficult job, just tedious and time consuming. Removal is the easy part, installation is a pain in the ar$e. Email me if you have specific questions not covered in the excellent DIY above.
 
#9 · (Edited)
Sorry for reviving an old thread, but did replacing the final stage unit fix the problem? My blower motor has begun to work intermittently. It's as if somebody is just turning the blower motor off with a switch periodically, but the climate control unit is staying illuminated and you can still switch the vents, etc. When the blower is running, it does not seem compromised in any way. I'm guessing it's either the motor or the FSU, but I wanted see what worked out in this case.

The problem also seems to go away after I've driven around for about ten minutes, and seems to show itself after I haven't driven the car for a while (four days or longer).

Ideas?
 
#12 ·
just replaced the fsr on my '01 525i, first the fan was coming on intermitently and just one day it went out completely, i ordered the fsu from bavauto and installed it , took me ten minutes, to remove and install, the trick is to remove the footwell cover on the passenger side( its where your toes would be pointing if you were seating on the passenger seat) it slides out pretty easy and then unscrew the carpet panel on the side of passenger compartment using a flashlight you'll be able to lcate fsu, push down on tab and disconnect the connector and pull fsu out, my a/c started working right after replacement with all speed controls functioning.
 
#14 · (Edited)
Just so I'm clear on this, is a blower motor that turns off intermittently (while the display stays illuminated) symptomatic of a failing FSU, or a failing blower motor? Mine runs completely normally, until it stops periodically and does not work at all.

I would think that a failing blower motor would display different symptoms, such as slower than normal fan speeds and/or strange sounds. Mine does none of that.
 
#16 ·
In my experience, blower motors don't work intermittently, they just stop working. I've done two of them, both PITA, but never a FSU. Usually you can tell if the motor is going to fail because it will start to make loud noises, chirps, or it starts to grind. There are new replacement motors on ebay for about 80 dollars shiped, and mine seems to work well. :thumbup:
 
#15 ·
seems ike the same symptoms that i had , when i start the car, either there would be no air coming out on the vent and then blows cold air at max or have max air at start ups and then dies later, until it toally went kaput, first ithought it was the contol module , so i pulled out the module and installed the module from my brothers 528i , same problem! after installing the new fsu problems been fixed, took the car for a weekend drive with my wife and a/c worked all day.
fsu is an easy fix hope you have same luck as mine.

regards
 
#19 ·
Yeah, they're about $45 from Pelican. I could probably get one from a junkyard for a few bucks, but who knows how long it would last, since they're apparently a common failure item. The other problem with the junkyard FSU is that I probably will have no way of testing it before I buy it.
 
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