Replacing the final stage unit/blower motor resistor (E39)

I truly believe this is my problem and I want to do it myself - do you think me - a chic - can do on her own?

That was a lot more work than I expected. It took me an hour to locate it. It is near the center of the vehicle, at the front of the center console, above where the passengers' left leg rests. (American configuration) Above and behind the passenger-side floor vent. After I Pulled the glovebox I found my '02 325i final stage resister was also hidden behind the blowers' electro-mechanical plunger. This had to be gently removed first. It was also held in place by two #20 torx screws. You have to be VERY careful not to damage the plunger linkage after you remove the screws and gently move it slightly out of the way to access the final stage resister. The screws are very difficult to see and remove, and even more difficult to replace. I must say that with my 325i model the job was substantially more difficult and would not recommend going into this job lightly! You need a small, powerful flashlight and a LOT of patience.

Spot on. Howeverr not so easy here in the uk because on a right hand drive its not the passenger side but drivers side and the pedals get in the way. However if it wasn't for wht i read hear i wouldn't have found the fault, never mind the locationof the fsu. Many many thanks refited a new fsuand so far so good. Part (part no 210110040 heater resistor -E39) coast me £41.71 from euro car parts.

godly this was a great help. recently i just felt my ac wasn't blowing as strong as it suppose to be. and some times it won't even blow any damn air.
then i read this. had to give it a shot. ordered the unit off ebay for 50$+10$shipping.
and put it on today. and god the air con now blow strong!
that was a easy done diy. the only tricky part was theres a tub holding FSU from sliding out. i didn't realize that. so took a while to get it out.
but the whole process was about 10 mins

thank u thank u

I have a 2002 330, I can not find the upper torq on the black duct piece in front of the FSU. I've reviewed both pictures on this forum, but still unable to find the upper torq.

Found the Torq, all done, eveything works

This was a great help article. I had a similar issue no air blowing. It was my first time working on a BMW it took me about 30-45mins to replace. thanks again it was very helpful.

Great write up and saved me a trip to the stealer! I replaced the FSU this morning and my fan is workin like champ once again! I echo the comments of some of the others using a pair of needle nose pliers to get the plug off was a winner. Once I got that off the FSU came off pretty easy as well, had to work it around the duct work under there but other then that...it was a snap!! Thanks again to my fellow Bimmerfest brother for postin this DIY!!!

we have a 1999, bmw. and the passanger side keeps get water all over the floor. is there someone who can tell me what the problem is. thank you

I am back with more hvac nightmares. My fan does not blow, period. I was able to get another fsu under warranty from the place I bought it from last yr. I put the new fsr in and nothing. I put my climate control panel in another 528 and it controlled the fan, no problem. I know that the unit works at least. So what's next?

Once you get the Blower Motot Resistor out is there anyway to check it to see if it is bad other than spending the $90 for a new one only to find out that that wasn;t the problem?

TX

S

Originally Posted by STM873

Once you get the Blower Motot Resistor out is there anyway to check it to see if it is bad

See post #150 of this thread.
The best test bench we have so far is as follows ...

Check the wiring harness terminals:
1,5) blower
2) +12
3) control input (in spite of being drawn as the collector of a bipolar transistor!)
4) ground

So I would:
A) spray WD40 on the contacts
B) check terminal 2 for voltage
C) put a two channel scope on terminals 3 and 1, and then 3 and 5

Thanks for the awesome write up that was easier then expected.

Another replacement, easy and quick, tough for a 6'4" to get into that space, but worth it.

I don't see the diagram and part numbers so here it is for the FSU on a 2002 E39

Thanks for the post Elvis. I thought I could trust my BMW mechanic and almost had him do this service for me for $260. He claimed $120 for the part and $140 for labor. The part cost me $60 and with your help I changed the part in 10 minutes.
Thanks again - now I just need to change my mechanic...

Thanks for the write up, i just finished doing this and it was as easy as described in the DIY. This is a great resource for BMW owners whom want to do their own repairs. I even switched out the blades on my wipers. I know it's not a big deal but after seeing that replacement parts cost up to $75 it was well worth 2 hours of a Saturday.

Elvis,

Thanks for this post - just ordered replacement FSU (£41) and will do it myself - saw your posting just in time (cancelled garage booking this morning)!!!!!! No doubt have saved loads of money!

Seems like a really common problem - great post.

Bit fidly on a right hand drive, but still only took 30 mins!!!!!! Well pleased.

Excellent DIY. Wife's fan fixed!

This is the easiest big fix I've ever done by myself. Every step was so clear cut I thought there had to be a pitfall awaiting me. None! Took me about fifteen minutes. Only hard part was disconnecting electrical wire clip from FSU, but wiggling and pulling worked. I don't even want to know what this would've cost me with my BMW repair guy.

Any tips on replacing the FSU? I'm having trouble with the tab. It's hard to push down the tab and pull out the unit at the same time.

Thanks.

Had same problem holding down tab with one hand and pulling out the FSU with the other. Not enough room for both hands! The answer for me was to do it with one hand by using pinky to hold down tab and thumb and forefinger to slowly wiggle and pull FSU out. It is slow and almost seems like you're not going to get it, but keep wiggling and pulling FSU while keeping tab depressed and it will come out.

Excellent post, took me about 30 minutes and I am not very mechanically inclined.

I've been having intermittent battery drains and thanks to your guide I managed to replace the FSU so thanks. Fingers crossed I won't find myself stranded again :-)