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

Originally Posted by Starless

This diy is for E46 cars only.

And, while we're at it, here are the DIYs for the E39 from the bestlinks thread.

- FAN CONTROL: poorly ventilated fan-control (FSU/FSR) modules that are practically sure to go haywire due to poor heat-sink design (1) (2) (3) (4) (5) (6) (7) (8) ... Autopsy (1) (2) (3) (4)

On my 2001 M3 convertible..

I am stuck in the middle of this DIY. Before I can have access to the FSU itself, the motor bracket is in the way where I'm having trouble getting out of the way. The lower screw was easily visible and is now removed, now the other screw?? where can I find it.. I've looked around and there nothing visible. Mind you the air duct is still intact since it doesn't seem to pull out easy. Please help!!

Originally Posted by marqe36

On my 2001 M3 convertible..

I am stuck in the middle of this DIY. Before I can have access to the FSU itself, the motor bracket is in the way where I'm having trouble getting out of the way. The lower screw was easily visible and is now removed, now the other screw?? where can I find it.. I've looked around and there nothing visible. Mind you the air duct is still intact since it doesn't seem to pull out easy. Please help!!

The arrow in one of my pictures points to its location. It's not easily visible but can be reached with a torx screwdriver. Just stick a torx driver there and you'll feel it. I took me a good 5-7 minutes to remove that screw, so be patient...

That was a great DIY pictorial. I replaced my blower motor resistor a week ago. I did it the same way you described in your DIY. Great job.

Originally Posted by kubi

I personally have no problem of buying parts from eBay. If you look at one of the links above, the part is Behr brand. So there is no question about the part. After I get the original part, the rest is not important to me. I believe the big sellers still have big margins on the parts although they sell less than BMW dealers. I think eBay is the main selling channel for the companies/individuals who have no access to big sellers.

Kubi, I also do not mind ebay for some purchases at all. If this is Behr and made in Germany that *should* be fine. The problem with FSUs is that even *good* resistors by reputable German brands still fail. It's important to go with the latest updated and improved version and part number issued by BMW. The one that I and other people used seems to be the latest improved part number and so far so good. If you ordered that ebay resistor just keep us updated how it works out for you. This is how we learn on this forum, mainly from experience of other people. If it fails, let us know and if it lasts a long time let us know too.

Update. I looked closer at those ebay resistors:

The part # of the ebay one ends in 3204. I've seen those made by Meyle too. They have 39 heat fins. It's an updated part number but might not fit all E46 properly and some have been known to fail shortly after installation
The part # I recommend ends in 0365. It's an updated part # too (latest I believe), has 58 heat fins and fits all E46 properly. Note, these resistors fail because of overheating. So more heat fins = better ability to dissipate heat.

Thanks so much for that detailed DIY! My blower motor gave me only one warning before it stopped working altogether. I found my part at AutohausAZ.com for $70...followed your steps...and now I'm back in business! It's a little tricky contorting yourself into position and trying to get a light on things, but if you take an occasional break to stretch out...you will get it done.

Haven't noticed any fluctuating fans speeds (unless it's on auto) but my ac is not blowing cold even after a fresh charge. Cool at best.

Could the fsu still be contributing to this even if the blower seems to be functioning normally?

My local mechanic thinks I may have an oil lock in the dryer or a jammed up expansion valve. I'm not sold on any of it. Input would be appreciated.

Great site btw.

Originally Posted by EnduroGuy

Haven't noticed any fluctuating fans speeds (unless it's on auto) but my ac is not blowing cold even after a fresh charge. Cool at best.

Could the fsu still be contributing to this even if the blower seems to be functioning normally?

My local mechanic thinks I may have an oil lock in the dryer or a jammed up expansion valve. I'm not sold on any of it. Input would be appreciated.

Great site btw.

Fsu has nothing to do with cold/hot air just the blower motor speed (pulsating, not working at all, etc). You need to have your ac system diagnosed. If you get a constant stream of air, your fsu is fine but you might have a leak somewhere

Incase anyone is still receiving thread updates, I had the same issue, 325 blowers just cut out one day, abruptly.

I followed DIY and installed the new FSU. Checked it and system is working fine.

I'm currently stuck though with reassemble. I'm really struggling with getting the Control Motor to reallign with the torx screws. As if almost the wires seem to be holding it up, I'm pretty sure at this point I'm going to give up completely on the top one, any suggestions on bottom one? Anyone else get held up at this point?

Besides that AWESOME DIY that even my Indy said "take it to a dealer" lol.

- hudock

*Update!! Got it. Didn't bother with top screw but finally got bottom to go in once i pressed on the wire hard enough to make it lay flat against the motor.

Everything works great, awesome DIY! Also, I'm a pretty big guy and it wasn't that bad, cramped for sure, my shoulders are a tad bit sore. Something that helped too was an Android Incredible, camcorder mode with flash, allowed me to easily see the screw up top!

Thanks again!

Originally Posted by hudock

*Update!! Got it. Didn't bother with top screw but finally got bottom to go in once i pressed on the wire hard enough to make it lay flat against the motor.

Everything works great, awesome DIY! Also, I'm a pretty big guy and it wasn't that bad, cramped for sure, my shoulders are a tad bit sore. Something that helped too was an Android Incredible, camcorder mode with flash, allowed me to easily see the screw up top!

Thanks again!

You are welcome. Glad you figured it out. Those motor screws can be annoying for sure.

Great DIY. Relaced with the modified BEHR & don't anticipate any problems. This was my first repair to a new to me BMW. Trying to solve the next issue with an intermittent no start.

Originally Posted by MLC2010

Great DIY. Relaced with the modified BEHR & don't anticipate any problems. This was my first repair to a new to me BMW. Trying to solve the next issue with an intermittent no start.

Does it always crank?

I had this issue, but over the weekend, I think the fan/blower quit totally. I can still hear the system turn on, but I'm getting no air/heat at all. Am I too late?

Originally Posted by maybebimmer

I had this issue, but over the weekend, I think the fan/blower quit totally. I can still hear the system turn on, but I'm getting no air/heat at all. Am I too late?

Do all the lights on the HVAC panel work normal? If yes, then you are probably not too late and it's likely your fsu

Ok guys Im a newbie in here but am haveing a problem with my AC/Heater fan blower motor. Friday I had to go jump my daughter 2001 330I off at her school. It charged up on the way home and cranked right up. Saturday morning it was dead again, Went and got a new battery and everything seemed fine. Monday, same thing dead battery. I brought it home myself but when I turned the car off I noticed the fan motor was running slow and I could hear it speed up and slow down and it would never cut compleatly off. I pulled the cabin air filter and you can hear the humming louder in there. So does this sound like the FSU has gone bad? I need to get this fixed so my daughter has a way back and forth to school. From the excellent DIY write up I do believe this will be an easy fix. Any help would be greatly appreciated.
Thanks everyone
Jimmy

Morning Zukman,

While doing research on replacing my FSU in my 02 325i, I came across others with your exact situation, and many times it was just the FSU.

I read that the FSU can cause the blower to stay on and killing the battery over night.

It was really easy to replace, took about an hour. Hardest part was I'm a pretty big guy and getting under that dash. As soon as I hooked up everything worked fine.

If your worried about spending the cash on an FSU or her needing the car back right away, I would imagine it would be ok to just pull the FSU.

Mind you, your heat goes away, but battery drain should in theory as well.

Anyone else think so?

- hudock

Originally Posted by zukman31

Ok guys Im a newbie in here but am haveing a problem with my AC/Heater fan blower motor. Friday I had to go jump my daughter 2001 330I off at her school. It charged up on the way home and cranked right up. Saturday morning it was dead again, Went and got a new battery and everything seemed fine. Monday, same thing dead battery. I brought it home myself but when I turned the car off I noticed the fan motor was running slow and I could hear it speed up and slow down and it would never cut compleatly off. I pulled the cabin air filter and you can hear the humming louder in there. So does this sound like the FSU has gone bad? I need to get this fixed so my daughter has a way back and forth to school. From the excellent DIY write up I do believe this will be an easy fix. Any help would be greatly appreciated.
Thanks everyone
Jimmy

Meanwhile she can pull a fuse to stop the fan. It's in the glove box, I do not remember the #, but you can look it up on the card in the fuse box. It will temporarily prevent from killing the battery.

See that, much better idea!

I tried pulling the fuses and it still would run. Im going to try to go tomorrow and get a new FSU and attempt to install it. This was a great DIY write up and I do not think it could be any clearier. Thanks so much for the write up and everyones input..
Jimmy

OK guys, Today I replaced the FSU. Believe it or not its actually a pretty easy job. 30 min. total. I cranked the car and everything worked perfect. I shut the car off and the blower motor quit running.. I was soooo dang happy. But I started listening and I could hear a very light noise coming from the Control unit sitting below the radio. I pulled it out and there is a small fan in the back of it that will not stop running. Has anyone ever had this problem? Any help would be greatly appreciated.
Thanks
Jimmy

Originally Posted by zukman31

OK guys, Today I replaced the FSU. Believe it or not its actually a pretty easy job. 30 min. total. I cranked the car and everything worked perfect. I shut the car off and the blower motor quit running.. I was soooo dang happy. But I started listening and I could hear a very light noise coming from the Control unit sitting below the radio. I pulled it out and there is a small fan in the back of it that will not stop running. Has anyone ever had this problem? Any help would be greatly appreciated.
Thanks
Jimmy

Yes I made a DIY for it too. It's a sensor blower fan (inside the HVAC unit). It's supposed to run for about 15 minutes after shut off, but silently. The solution is to lube the little bearing

Just an update re my FSU problem: Fan stopped working, but never did slow down. Anyway, as you may recall, I noted that there was a thread that said pulling the two fuses that the FSU uses and replugging them in, is worth a try. Well, did that several months ago, and the fan is still working as it should.

walk through was freakin awesome!! it took me 30 minutes and i was done.. thanks for the help i dont think i woulda known what was wrong with my 325 if it wasnt for you guys!! keep up the good work!

Hi Everyone,

I have a 2000 323i and ran across the FSU (BLOWER MOTOR RESISTOR) issue, Blower turning on and off by itself. Saw Starless's DIY which was amazing and easily felt I could do the job. I never buy from the stealership unless absolutely necessary and have always been very fortunate to find what I need on eBay or other online sources.

After doing an eBay search for the FSU, I came across this very unique aftermarket FSU. I have included links to the eBay ad, and the manufacturers website. This thing is short of amazing and you'll see why. (NO COOLER PRONGS & RUNS AT 90 DEGREES WHILE OEM PARTS RUNS AT 250 DEGREES, DID I SAY, NO COOLER PRONGS?)

And GET THIS only $27.45, yes $27.45 plus about $6 bucks in shipping. I have been using it for sometime now with no issues whatsoever and unless I am having a placebo affect, I can swear I'm getting more pump from the blower. (or maybe thats the cabin filter I just replaced? dont know?)

In any case, I was waiting for this thing to stop working or not work at all after installation but honestly, it's just an amazing part. Took me about 45 minutes to complete the installation and a few back ache pills but all is working perfectly. I heard of some people paying $135 at the stealership which is just insane. Hope this helps some of you!!! They also have a reseller program. This could be the find of the year.

http://cgi.ebay.com/ebaymotors/BMW-F...ht_1329wt_1167

http://betterpartx.com/