DIY: FSU (aka Blower Motor Resistor) replacement pictorial guide

My story - The climate control in my 2000 328i started acting up about 3 weeks ago. As any of you know that it has happened to, it is extremely annoying especially in the middle of summer. A brief google search confirmed that blower motor resistor was indeed the problem. I read some of the DIYs on how to replace it, but I am really bad at these sorts of things, so I didn't think I could handle the repair. It seems that in a 5 series this is a much easier procedure. So I contacted some local places to inquire about replacement cost. An independant BMW mechanic wanted $260 to do the repair, and dealer wanted $400+. So, was about to schedule an appointment when I found this thread. The pictures are so much clearer than the other DIY that I found, and it inspired me to give it a try. Ordered the part from Eeuroparts as OP suggested. Part arrived in 2-3 days. Figured I would get started tonight and see how far I could get. Bottom line - I was able to complete the entire repair in about 45 minutes. THANK YOU OP!!! Again, if I can do it, it can be done by almost anyone. The 2 parts I had a bit of trouble with were 1) Removing the floorboard trim piece - hard to get the final clip off - had to push really hard 2) Getting the FSU out of the socket - it was really hard to get it unclipped, but once I did I was able to wiggle it out - it was much easier to get the new one in.

A few of my own thoughts:
1) My FSU did have 2 screws in it, despite many reports that the factory doesn't put the screws in. Odd, but it wasn't hard to remove them.
2) A magnetized T20 definitely helps
3) I was able to kneel on the ground outside the car looking in to do the replacement - didn't seem too hard to do it that way
4) My best tip - I used an adjustable headlight to see what I was doing rather than a flashlight. It made it really easy to see what I was doing.

Many thanks OP!

FWIW, we've been trying to find which FSR 'brands' are the reliable ones over in this FSR/FSU autopsy thread in the E39 forums ...

So far, we "think" the only reliable FSR is Sitronic/Bosch ... but time will tell of the others ...
Recommended:
- Sitronic/Bosch

Not recommended:
- GKR
- Behr
- Valeo,
- Siemens

Certainly not recommended:
- Meyle
- Hella
- Uro
- Denso
- Power Pro

Let's all pitch in to report the bad ones (e.g., GKR), so we can understand the good ones.

^ I'm not sure all this applies to E46. BMW FSU part numbers lead to 2 brands - Behr and Meyle. The part has been updated many times and the final version of Behr (0365 part number) seems to be problem free.

Originally Posted by Starless

^ I'm not sure all this applies to E46. BMW FSU part numbers lead to 2 brands - Behr and Meyle. The part has been updated many times and the final version of Behr (0365 part number) seems to be problem free.

FWIW, I understand. The electronics may be different. However, the symptoms are the same, the solution is the same, and even the brands are the same ... so I'll wager there's more similarity than differences.

So far, we're staying away from anything with GKR stamped on it, either in the metal or on the sticker. If it says Behr, you have to be careful as it also says GKR and BMW. Some even have FOUR brands listed.

So, it's confusing at best - but that's why we're all working together to identify which FSR brands to avoid in that thread where we took 'em apart.

It took me 4 hours (including going to get the replacement part) and a lot of frustrating moments and feelings of claustrophobia, but with my wife's help (her hands were small enough to push back the clip and remove the FSU (blower motor resistor).

Then we were off to BMW for the part: $134.00 ( I didn't want to wait to fix it)
The reassembly was a little tricky and only took about 1/2 hour and we were off to the car wash.

I did manage to break both the clips off the SDU harness, so be careful not to remove the harness until the FSU is out. Even with the broken clips the unit connected snugly.

Also, it was tricky getting the heater duct out (I do not see how you can do this job otherwise) and back in, but take your time you will figure it out. Pull back gently on the leather trim till it pops loud, but no more. You will not do any damage you can see. You have to work the heater duct out from the back to the front (use a light to see).

Drink lots of water and take several breaks. Once you do this once it will be a piece of cake the next time. I was moving nicely until I had to deal with the heater duct removal. Take your time here....

It helps if someone can hold a flashlight and hand you tools as you go. You will be working in a very tight space, so be prepared. My feet were dangling over the reclined front seat and out of the open back passenger door.

Thanks everyone for the threads. I couldn't have attempted this without you.

I strongly recommend anyone replacing the FSU on an E46 buy the following:

Craftsman Specialty Tool Set 4717

http://www.sears.com/shc/s/p_10153_1...7000P?prdNo=13

That set contains a magnet on an telescoping handle that is perfect for removing the 4 Torx screws so they don't drop into a black hole, never to return. The kit also includes a Phillips/Torx screw starter that made reinstalling the Torx screws a breeze. I also used the bent end of the scriber to help me release the clips on the FSU wire harness plug (although maybe I could have released the plug easier after sliding the FSU out).

If you don't already have Torx screwdrivers, Craftsman has an inexpensive set for about $10 but I recommend that you instead buy their better quality drivers.

http://www.craftsman.com/shc/s/p_101...5&blockType=L5

The handle gives a much better grip and the shank is much longer, which also was a help on this job. You can buy the set of 5 drivers for about $35 or just the T20 for about $7.

After all the work I did yesterday replacing the FSU, I am frustrated today....the vents on the right drivers side are blowing cold air, the vents on passenger side are blowing warm air...did I do something wrong? Did I disconnect or not reconnect something? Please advise....

Originally Posted by cesmoot

After all the work I did yesterday replacing the FSU, I am frustrated today....the vents on the right drivers side are blowing cold air, the vents on passenger side are blowing warm air...did I do something wrong? Did I disconnect or not reconnect something? Please advise....

You did nothing wrong. It's a classical bmw symptom of low/leaking AC refrigerant. I'd go to an indy shop and have them evacuate the system and refill it with the correct amount of refrigerant. In many cases just this solves the problem but if you have a persistent leak then it will need to get fixed too. Keep us updated.

Alex, I called BMW; they were kind enough to give me the shop foreman after hours. He said I should add freon first. Went to Auto Zone and purchased the can with the gauge etc for about 27.00.

The gauge read in the blue zone, but I added more till it was just shy of the yellow area. What do you know...I drove the car home and noticed that the air was getting colder on the passenger side as well.

I suspect I may have a slow leak though and will keep an eye on it.

Thanks Alex. You were right on....Boy am I relieved... I love this forum

I did it! Have never done a single car repair in my life, but my husband is in Afghanistan and I'm stuck at home with two little kids and the BMW dealer and repair shop are both 30 minutes away. Followed the instructions and now the AC is blowing cold again. Hallelujah!

One small issue, though...as I was wrestling everything back in place to reassemble it, I managed to pop the metal rod off the control motor. When I finally got the control motor back in place, the rod was back in the top (resting in the round yellow disc) but I don't think it was snapped in or attached. How important is that piece? Any idea what will happen? Hope I haven't made things worse...

Originally Posted by jenshields

I did it! Have never done a single car repair in my life, but my husband is in Afghanistan and I'm stuck at home with two little kids and the BMW dealer and repair shop are both 30 minutes away. Followed the instructions and now the AC is blowing cold again. Hallelujah!

One small issue, though...as I was wrestling everything back in place to reassemble it, I managed to pop the metal rod off the control motor. When I finally got the control motor back in place, the rod was back in the top (resting in the round yellow disc) but I don't think it was snapped in or attached. How important is that piece? Any idea what will happen? Hope I haven't made things worse...

Jen, welcome to the forum and congratulations on the first repair!

My understanding (although I'm not 100% sure) is that the function of that motor with the rod is to switch between the outside airflow and recirculation of air withing the cabin. If my understanding is correct than this system will not work properly with the rod disconnected. I use this function occasionally and could definitely live without it. But I also like everything to work 100% in my car, so it's up to you how important this is

Originally Posted by jenshields

I did it! Have never done a single car repair in my life, but my husband is in Afghanistan and I'm stuck at home with two little kids and the BMW dealer and repair shop are both 30 minutes away. Followed the instructions and now the AC is blowing cold again. Hallelujah!

One small issue, though...as I was wrestling everything back in place to reassemble it, I managed to pop the metal rod off the control motor. When I finally got the control motor back in place, the rod was back in the top (resting in the round yellow disc) but I don't think it was snapped in or attached. How important is that piece? Any idea what will happen? Hope I haven't made things worse...

Now that you've entered the world of car repairs, you have learned that it's important to not create a new problem when you're repairing an old one. So get back in there and fix it right. In the future when you see a post about FSU's or outside air control motors you'll qualify as our new resident expert. Keep up the good work!

Originally Posted by Starless

^ I'm not sure all this applies to E46. BMW FSU part numbers lead to 2 brands - Behr and Meyle. The part has been updated many times and the final version of Behr (0365 part number) seems to be problem free.

I hope so. I just ordered my FSU at eEUP website and its manufactured by Behr.
http://www.eeuroparts.com/main/partd...id=64116920365

Originally Posted by READYON3

I hope so. I just ordered my FSU at eEUP website and its manufactured by Behr.
http://www.eeuroparts.com/main/partd...id=64116920365

When you receive it, let us know where it was manufactured. Most of the Behr parts used to be made in Germany, now some of the stuff is made in China.

Originally Posted by catso

When you receive it, let us know where it was manufactured. Most of the Behr parts used to be made in Germany, now some of the stuff is made in China.

He ordered the same part # from the same web site as I did. And mine IS made in Germany. Everything has been good so far.

Originally Posted by Starless

He ordered the same part # from the same web site as I did. And mine IS made in Germany. Everything has been good so far.

That's good to know, except for the fact that I just bought a new Behr aux cooling fan that says "made in China" on it.

The part will be here in a couple of days. the wait is driving me crazy. LOL.

finally came in. Gonna do the install this weekend.

Made in Germany.

I read somewhere where a person had this problem and simply replaced (I think by replaced he meant pulled out and put back in) fuse 50 and that solved his problems. I have a fluctuating fan speed sometimes when I turn the unit on then it evens out. I'm trying it to see if it works but has anyone heard of this?

http://www.bimmerwerkz.com/forum/3-s...tor-46839.html

Originally Posted by jeffmr

I read somewhere where a person had this problem and simply replaced (I think by replaced he meant pulled out and put back in) fuse 50 and that solved his problems. I have a fluctuating fan speed sometimes when I turn the unit on then it evens out. I'm trying it to see if it works but has anyone heard of this?

http://www.bimmerwerkz.com/forum/3-s...tor-46839.html

Although I got the new FSU, I figured I'd give the "fuse pull" approach a try first to see if it resets things. Certainly easier to do and worht the try. The blower has been behaving erradically: Speeds don't vary, but blower just turns off and on at the oddest times. Anyway, it's my wife's car (LOL as long as she doesn't see this).

Excellant instructions & pictures, followed everything to the T, very informative, you did not miss anything, it took me about 90 minutes. I had to pause from time to time (I have a bad back ) Thanks Again, greatly appreciate it.

Originally Posted by Starless

It was my turn to replace the FSU (blower motor resistor). I just got tired of the pulsating pattern of the blower and its shutting off on its own accord. It is especially frustrating in the 100F degrees St. Louis weather. I ordered the part through one of my favorite sites: www.eeuroparts.com that has great prices and both OE and aftermarket parts. The FSU is made by Behr (OEM). The cost was $59.99 shipped. It took an hour to install and it was a pain in the neck (literally) due to its location under the dash. If you have problems with your back/neck/shoulders I’d recommend to delegate this repair to a shop technician (hopefully without these problems). You have to spend some time in the area below the glove box on your back and side with your legs on the passenger seat. There is simply no other way.

The DIY is in the pictures. Sorry if I missed something. But that’s just pretty much the way I did it. I’ll just mention it here one more time that I did not find it necessary to remove the air duct and control motor to get to the resistor like some other diys suggest. Of course it will make things a little easier but will take more time. And I did not want to spend more time on the 95F degrees evening sweating in the footwell of the car. So here is the pictorial guide:

Hey guys. newbie here.
I'm about to order this part from eEuroparts but I wanted to know....

IHKA is on in any situation (pre-ignition/ignition) but there is no air coming out at all... would this be the culprit?

I had disconnected the IHKA because I was running some cables through there for a headunit. I connected the IHKA back up and it would light up, but there was no air coming out into the cabin.

might this be the reason why it's not turning on? could I have shorted it and not even realize it?

Hello All,
This is a great forum, thanks so much.
Now...I know the FSU issue has been batted around quite a bit, but here is my issue.
My ac blows cold-..okay cold-ish, except on the driver defrost and floor vents. No matter what the setting is-the air there is hot. Quite hot. Not good in Texas. The other thing is-when I turn the car off I hear a kind of buzz that seems to emanate from behind and to the left of the glove box. Is there where the FSU is on my car? And could that be causing my ac problems? The battery also drains after a couple of days without driving.

Lots more bothersome things going on with this car, but those are the major ones.
The car has 230k miles and has been an absolutely fabulous car for me, but not having proper ac is a drag. I can repair this myself as long as I know where to look for the part. It's not under the passenger beneath the glovebox--at least not that I can see (I removed the cover-which in this case, has two screws-you don't just yank it off).

Help is greatly appreciated.

Originally Posted by slangups

Hello All,
This is a great forum, thanks so much.
Now...I know the FSU issue has been batted around quite a bit, but here is my issue.
My ac blows cold-..okay cold-ish, except on the driver defrost and floor vents. No matter what the setting is-the air there is hot. Quite hot. Not good in Texas. The other thing is-when I turn the car off I hear a kind of buzz that seems to emanate from behind and to the left of the glove box. Is there where the FSU is on my car? And could that be causing my ac problems? The battery also drains after a couple of days without driving.

Lots more bothersome things going on with this car, but those are the major ones.
The car has 230k miles and has been an absolutely fabulous car for me, but not having proper ac is a drag. I can repair this myself as long as I know where to look for the part. It's not under the passenger beneath the glovebox--at least not that I can see (I removed the cover-which in this case, has two screws-you don't just yank it off).

Help is greatly appreciated.

This diy is for E46 cars only. I'm not sure if E36 FSU is similar or not but if you post in the E36 section of the forum I'm sure you'll get better help there. Here is the link:

http://www.bimmerfest.com/forums/forumdisplay.php?f=97

Welcome to bimmerfest!

thanks very much