Replacing Final Stage Blower Resistor pack

[randywalters]

I have a 94 325IS and my blower only work on high. I have replaced the blower motor resistor about four times now only to have it fail within a week or so. The last time however, I replaced the blower motor relay with one from my parts car and it lasted a couple months. However, again the resistor has died. Thoughts? Help?

Easy one. Your blower motor is binding up and overloading the resistor pack, causing it to fail.

Strange - you posted the same thing almost two years ago in another thread, did you not heed the advice posted back then?

http://forums.bimmerforums.com/forum...8&postcount=17

http://forums.bimmerforums.com/forum...1#post17352577

Replace or repair your blower motor. You'll continue to blow replacement resistor packs until you solve the root problem (the bad blower motor).

[Marknhl]

Easy one. Your blower motor is binding up and overloading the resistor pack, causing it to fail.

Strange - you posted the same thing almost two years ago in another thread, did you not heed the advice posted back then?

http://forums.bimmerforums.com/forum...8&postcount=17

http://forums.bimmerforums.com/forum...1#post17352577

Replace or repair your blower motor. You'll continue to blow replacement resistor packs until you solve the root problem (the bad blower motor).

Thanks for the reply Randy! And, lol Well I guess not! I don't remember reading that bit about the blower motor binding up. At least while I'm reading it now, it seems to be a definitive answer as to why this problem continues to occur. I'll tell you that I really didn't and still don't want to replace the blower motor itself, but I don't remember it being the absolute answer. And if it wasn't - I wasn't going to replace it.

One thing I wasn't clear on what they were saying... they mentioned that maybe you can lube up the bearings that are in there now... Is it possible to do this while it's still in the car or no? My blower motor doesn't make noise anymore but it certainly use to (it also doesn't work on low speeds :P) I'm sure it still needs to be lubed up and cleaned. I'm just hoping I can reach and do this while it's still in the car?

[ty20404]

Okay, I'm almost certain that I know what I need to replace, but I want someone else to tell me before I spend the money.

Here's what mine does:

Everything works fine most of the time but randomly the fan will stop blowing all together, but the Climate Control Module still has all the lighting and from what I remember I can still hear the A/C clutch kicking on and off as it should. The Module will still function and all the buttons will work, just no air blowing?

What's the answer? (99 328is w/ Climate Control) TIA.

[baragos]

can someone help me to send the diagram of bmw e36 climate control diagram i really need that urgently

[Blaine0724]

my blower and ac had these problems.. coming on like its possessed and staying on when the car is off but only one time and then my car happened to fill up with smoke so i had to disconnect the battery to stop the fan from blowing

[BadBoostedBmwM3]

I'd like to add a thank you to the OP. I was able to successful replace and fix problem about 6 weeks ago because of this thread.

[Instantaneous]

I'd like to add a big THANKS to the OP for the DIY. Helped me out a great deal. The blower is working great and the "thunk" noise from behind the center vents is gone.

As another poster stated, I didn't have to remove the footwell air vent to get to my final stage.

In case you don't have a torx screwdriver/bit, you can use a square bit as an alternative. Just be careful not to round out the head.

Funny thing: I had the final stage replaced at the $tealer last time and the tech missed the hole for one of the screws. So he just jammed it in there, probably because he was too lazy to get back there and see where it should go.

[josh marcus]

So ac/heater have been turning themselves on and off for some time now, and I decided to fix it. Upon doing some research i thought it may be the FSU, so I bought a new one and just replaced it. Unfortunately it has not corrected the problem.
Any ideas or suggestions?

[Chokingdogs]

So ac/heater have been turning themselves on and off for some time now, and I decided to fix it. Upon doing some research i thought it may be the FSU, so I bought a new one and just replaced it. Unfortunately it has not corrected the problem.
Any ideas or suggestions?

How much research did you really do?

Pretty well documented the two most common issues with digital HVAC system.

1 - randomly going on / off - lights of display - and no control of fan speed or other functions, usually accompanied by the A/C clutch kicking on when the control head goes "dark". That the capacitor issue, where you need to yank the unit and either re-solder the caps ( as some have done with success ), or removed the old ones and solder in new ones.

2 - Fan speed not controllable with manual inputs of the speed on the head unit. Fan will either not blow at all, blow at a ( or up to ) constant speed regardless of setting, will sometimes increase/decrease on it's own to whatever it's set to, all this is accompanied by a fully functional head unit, in which you have control over all the settings - auto, defrost, individual vents, etc. EXCEPT fan speed. Replacing the FS resistor pack fixes this 98% of the time.

You had problem #1, but used the fix for problem #2. All isn't lost though, the FS units go bad over time, so at least you now have a fresh one. I assume you bought a new one, or known good working used one.

[josh marcus]

I did enough research I thought, but i think they were explaining a problem with e39 not e36. Thanks for the reply I have found a site with instructions on how to replace the capacitor, and will let you know how that works for me.

[josh marcus]

Thank you for the fast reply, I went ahead and put on a new capacitor and everything works great!
Found awesome instructions on how to go about it on:

http://www.macadamizer.com/bmwfix.html

Hope that helps people in the future!

[Merph]

Hi all. Well I was not sure which problem I had so I did the cheapest first. I replaced the capacitor. I got everything at Frys electronics all for around 12.00. One piece of advice if you decide to do the capacitor fix. When your trying to take the circuit board out don’t try to take out one side and then the other. When your pushing the tabs, push one side just a little and then do the same to the other side. Kinda sliding both sides out at the same time. Every time I got one side out I could not get the other out, its very tight. Well I just got my Fsr in the mail today cause the capacitor didn't fix my dead blower. I replaced it and walla, my blower is back and blowing.. I got my fsr off of ebay for 41.90 including shipping. That’s the best deal I could find. Here is a link to the web page.http://cgi.ebay.com/ebaymotors/BMW-3...ht_3949wt_2178
By the way I have a 97 M3 coupe. Thanks for the great DIY. Saved me a bunch of cash. Thanks and good luck to everyone tryn to fix your rides.

[DiegoMesa]

I have an obd1 1995 m3 and my a/c isn't blowing as hard as it should. Do I have to replace the same part you did or is that only in 1996+? Amy idea what I need to replace?

[Pdwight]

I just acquired my 98 323 from a friend, I did the capacitor first because it is such an easy ting to do and I keep capacitors in my shop all the time (I do some PC board repair). I ordered a FSU that is mostly plastic from Rock Auot Parts for 41 bucks an installed it to no avail.....I am going to try jumpering the blower motor ti see if it will run at the FSU plug.....it used to run ocasionally when it was below 60 deg outside and would control properly....now nothing....I dont mind replacing the motor but if it is anyting elae I sure want to repair that before I tear the front of the assembly off replacing a blower motor. Any help or directions to look at are greatly appreciated.

Sincerely
Dwight

[hinzm3]

Got in my car this morning figured I would drive it for the 4th time this year and the blower wouldn't work. The AC compressor died on my 06 civic yesterday and today my E36 blower wouldnt work so all 3 of my cars had inop AC's lol.

Came home and took the cowl off. The blower motor was getting 8volts once everything was on. I put 12v to the motor and it worked great so I buttoned it up and ordered an FSU. Just for the heck of it I took the underpanel off and jiggled the wires to the FSU and it started working. I'm going to replace it anyways but hopefully it gets me through the weekend!

Now I have to replace the stupid compressor on the FWD civic

[rdthoms]

did this today, pretty easy, getting the bolster off was harder than putting it back on (a pleasant surprise as I had geared up for battle)!

My symptoms were that I could move fan control up/down but fan would not blow at all. Interesting that simply pulling the fan fuse and reinserting would reset and then the fan would work fine for a few days. Anyway, not 100% sure the FSU was the problem but figured that was the next thing to replace (I've done the capacitor fix a year or so ago). Thanks to OP for the DIY.

[csecse]

I have had both the bad capacitor in the control unit problem (fixed it with a replacement cap a couple years ago) and now a faulty FSU (waiting for a new one to arrive from pelican parts).

I wanted to share a few tips on living with an inoperable fan while waiting to repair it.

If you want heat, you should be able to turn up the temperature on the climate control and direct heat to the floor vents. When traveling faster than 20 mph, there should be enough ram air to force hot air out the vents.

If you want air conditioned cool air, it gets a little trickier. The digital climate control seems to default to recirculate (even if you don't have recirculate selected) if you set the temperature setting lower than the current temperature inside the car AND you have the A/C on. This is a problem if your fan doesn't work, as ram air cannot be forced through the ducting if recirculate is set.

So, you need to trick the Climate Control into turning off recirculate. To do this, select A/C and select the dashboard vents only (not floor or defrost), and turn the temperature wheel to maximum cold - this will ensure only cool air comes out the vents. Finally, set the temperature to the upper maximum (90 degrees F) - this will override the climate control defaulting to recirculate if the cabin temperature is higher than the selected temperature. Using this trick while driving at freeway speeds kept the car reasonably cool even in 95 degree weather with no fan. Let me know if this trick works for you!

[p318i]

Okay, I'm almost certain that I know what I need to replace, but I want someone else to tell me before I spend the money.

Here's what mine does:

Everything works fine most of the time but randomly the fan will stop blowing all together, but the Climate Control Module still has all the lighting and from what I remember I can still hear the A/C clutch kicking on and off as it should. The Module will still function and all the buttons will work, just no air blowing?

What's the answer? (99 328is w/ Climate Control) TIA.

Mine is doing the same thing as yours. I was thinking maybe a loose connection somewhere because it started to work on its own for a couple of hours, but it has stopped working again. I'm going to try the FSU... But with all this capacitor talk, I'm wondering if that is the problem instead?

EDIT: So I replaced the FSU. My air and fan worked great for about a month. No strange noises or inconsistent fan speeds. But then the past couple of days the fan was being obnoxiously loud which lead up to today when it stopped working all together... again. Back to the drawing board, I suppose.

[Pdwight]

I went through this 2 months ago.

If your digital control unit goes off and on on its own, like it has a mind of its own...the display goes blank and then comes back on

You need the capacitor fix


If your blower comes on after the car has sat over night or its cool outside, the blower comes on and then you stop 10 minutes later and it will not come back on (or if it makes any noise at low speed settings) you have a bad blower or it is on its last leg. Replace it now while the weather is nice, you will want heat and defrosting ability in 2 months.

Also if your car has over 90K you will need a new blower. You can take it out, clean it, lube it and it will run like a champ for about 4 to 6 weeks and your back at square one....it is such a long job to get it out go ahead and replace it.

The mysterious FSU

This is nothing but a glorified light dimmer, if you look at the connector you will see a small size blue wire, this is the control voltage from the digital climate control. Put a Meter on this and step the blower from lowest setting to highest.....the voltage will go from around 2V (DC) to 8V at the highest setting.

If you want to test your FSU have it out and connected, put a meter across the wires that go to the blower, now step the blower motor from highest to lowest setting , the actual voltage across the blower motor wires at the FSU plug will go from around 5Volts to 12 Volts at the highest setting. If it is doing this then your Digital Control unit is fine and so is your FSU...its your fan motor. Last unplug the FSU (hedgehog) and test the resistance across the motor, it should be fairly low....if memory serves me correctly around 40 to 60 ohms.

This might sound like a ton of work but all this can be accomplished in 30 minutes and will tell you what is actually wrong instead of just buying parts and hoping for the best.

[bladerealm124]

Just did this fix this afternoon using your DIY. My fan hasn't really worked since I purchased the car. Came on once randomly for a very short time then failed again. But it's working great now. Can't thank you enough, took about 30 minutes total to complete, the hardest part was getting the torx screws out and back into the FSU. The upper one was lodged right behind a thick wiring harness that I couldn't budge. Luckily I was able to squeeze in there with a ratchet and get it out. I never pulled the air duct or the OBD connector either but they weren't really in the way. Worked immediately after plugging it in. I also used a new style FSU that I purchased from Ebay by a company called BPSX Better Parts Solutions. They also have a website http://betterpartx.com/products.aspx Not sure how it's going to hold up but this new style has none of the big or small "hedgehog" pins that are commonly seen in the original and aftermarket Behr FSU's. I took a chance with the new style unit but I'm hoping for the best, I'll let you guys know if it fails. Thanks again

[p318i]

I went through this 2 months ago.

If your digital control unit goes off and on on its own, like it has a mind of its own...the display goes blank and then comes back on

You need the capacitor fix


If your blower comes on after the car has sat over night or its cool outside, the blower comes on and then you stop 10 minutes later and it will not come back on (or if it makes any noise at low speed settings) you have a bad blower or it is on its last leg. Replace it now while the weather is nice, you will want heat and defrosting ability in 2 months.

Also if your car has over 90K you will need a new blower. You can take it out, clean it, lube it and it will run like a champ for about 4 to 6 weeks and your back at square one....it is such a long job to get it out go ahead and replace it.

The mysterious FSU

This is nothing but a glorified light dimmer, if you look at the connector you will see a small size blue wire, this is the control voltage from the digital climate control. Put a Meter on this and step the blower from lowest setting to highest.....the voltage will go from around 2V (DC) to 8V at the highest setting.

If you want to test your FSU have it out and connected, put a meter across the wires that go to the blower, now step the blower motor from highest to lowest setting , the actual voltage across the blower motor wires at the FSU plug will go from around 5Volts to 12 Volts at the highest setting. If it is doing this then your Digital Control unit is fine and so is your FSU...its your fan motor. Last unplug the FSU (hedgehog) and test the resistance across the motor, it should be fairly low....if memory serves me correctly around 40 to 60 ohms.

This might sound like a ton of work but all this can be accomplished in 30 minutes and will tell you what is actually wrong instead of just buying parts and hoping for the best.

Do you have any suggestions on where to get a new blower or what kind would be needed? Or if there is a DIY on how to replace it? I am hoping it's as easy as the FSU was to replace...

[Pdwight]

I purchased mine on Ebay, make sure you get one with removable cages...this is very very important unless you want to bend some of the sheet metal on your car for installation (I did not)

this is the DIY Guide I used
http://www.dvatp.com/bmw/diy/hvac_blower/

it is superbly written and detailed images are included.

I also replaced my cowl when I did mine, I got a new one from Husker BMW for around $38

That's all the good news, now for the bad

This is not a hard job, but it is a very long job. I have done this twice and it still eats most of a full day up. I used two folding card tables for parts removed and several containers to group screws and fasteners into their separate categories so parts did not get interchanged. Do not think for one minute you can take your blower off and clean and lubricate it and it will be fine...I made this mistake and had to do the job twice in 8 weeks. Like I said this is not a had job but it is long and will kill a day if done properly. While your in there clean out the cowl drains and any other foreign matter you find. Get a windshield wiper removal tool (15 bucks at Advance Auto) you will need it as well as some zip ties. Also lubricate your windshield wiper assembly once you have it off.

Here is a blower motor like I used

http://www.ebay.com/itm/92-93-99-BMW...item5ae38040bc

However make sure before you purchase the blower motor you email them and ask if the cages are removable, if not move onto another supplier. Do not even think about buying a used blower or a rebuild kit...get a new unit.

Let me know if I can help or answer any questions, lots of member helped me when I got stuck on my job (Thanks Scooper)

Dwight

[bladerealm124]

So my new non-hedgehog style FSU failed after less than 2 months. Haven't had a chance to pull it out and test the voltage but the symptoms are exactly what I experienced before I replaced it(no fan). Luckily the heat usually seeps out enough to defog my windshield but once it gets colder I don't think this will be the case. Any idea why it would fail so soon? I'm pretty sure the unit has a lifetime warranty so hopefully I will be able to get a new one ASAP. But I'm afraid it will just fail again in time. Is there an underlying problem I'm missing that would cause my fsu to fail again that quickly? Also before I replaced it it worked every now and then for a brief time but now my fan is completely shot. Thoughts? Thanks

[Pdwight]

Have you replaced your blower motor ? as the bearings get older they draw more current to operate. Also as they get older the brushes get worn and the blush material builds up in the commuter ring on the motor causing it to draw more current. The more current it draws the shorter the life of the FSU

[bladerealm124]

No I haven't replaced the blower motor as I've only owned the car for 2 months. I'm assuming it hasn't ever been replaced. But when it was working after I replaced the fsu it wasn't make any odd noises and it worked great. But is it possible for it to be worn without any signs? I've heard its kind of a pain in the ass to replace too, any way I can check if this is the issue? Thanks