Fan working intermittently

[dgregp]

I just purchased a 91 850i and the Fan blower works intermittently. Usually, when I start the car it's not working. I then will turn it from the lowest setting to the highest and usually this has no effect. Then, as I'm driving around, it will randomly start working. I have not found any particular pattern for when it works versus not working. Generally, it does not work.

Any thoughts on what the problem might be and how to fix it?

Thanks!

[Timm]

The two contenders are the Final Stage Unit (known as a Sword because of its shape) and the blower motor itself. When the Sword fails the blower usually works at only full speed (past the click at the fastest setting) - this is because there is a relay that bypasses the electronics on the Sword itself. If the blower doesn't run at full speed but just randomly starts going then the blower itself is the most likely cause.

[dgregp]

Tim,

Thanks for your response. Based on your experience with the 8 series, should I replace the Sword and see if it fixes the problem (I can probably do this myself) or assume its the blower and take it to my mechanic? I know its hard to know but would appreciate your thoughts.

Thanks - Greg

[Timm]

Does the fan work reliably at full speed?

[dgregp]

Yes, it does. So, I assume it's the Final Stage Unit? Any idea where I can find one for a 91 850i? Everywhere I have looked online does not have one for that model.

Also, I noticed air is not blowing out of the right side dash and door vents. I assume this is a flapper problem? If so, any advice on what to do about this issue?

Thanks so much!

[TedBobo]

Yes, it does. So, I assume it's the Final Stage Unit? Any idea where I can find one for a 91 850i? Everywhere I have looked online does not have one for that model.

Also, I noticed air is not blowing out of the right side dash and door vents. I assume this is a flapper problem? If so, any advice on what to do about this issue?

Thanks so much!

Did you try here?

https://www.programainc.com

[Timm]

Yes, that's probably the Sword - and it is the same on all model years

[dgregp]

Thanks for the info, is this the Sword I need? https://www.programainc.com/item_det...ategory=29&sf=

Also, do you have specific instructions (with pic's) on how to replace the sword?

Thanks!

- - - Updated - - -

Thanks, I believe this is the part I need? https://www.programainc.com/item_det...ategory=29&sf=

[Timm]

That's the one - easy on a LHD car (compared to the RHD version that needs the steering column removed) something like this:

https://www.meeknet.co.uk/E32/Microfilter/Index.htm

[DavesNotHere]

FWIW, the FETs can be replaced for much less than a sword if you're handy with a soldering iron. Might want to try reflowing the solder on your sword before replacing it.

and Timm... thank you for your coolant valve pics. I just replaced my blower (squeaky, making me mental) and the pics were helpful. I'll post a write-up with pics soon.

[dgregp]

Tim,

Thanks for all the info. Just ordered the Sword - should be here in a few days. BTW, do you have pic's and specific instructions on how to install on a LHD car? You mentioned in your link, that most of the info that you found was for a LHD. Can you direct me to any info pic's on how to replace the Sword on a LHD?

Thanks so much!

[Timm]

I've got nothing - but apart from removing the driver's side kick-panel you remove the PASSENGER one - it's a lot easier on a LHD car!

https://www.google.com/search?q=swor..._AUoAHoECAEQAA

[dgregp]

Thanks for all of the help. Just replaced the Sword and the fan works great!

[TedBobo]

Thanks for all of the help. Just replaced the Sword and the fan works great!

What's the degree of difficulty ?

[olinjohnston]

What's the degree of difficulty ?

This is one of the easy E31 jobs I think. Took me about 20 minutes.

[EEDegreeToDrive]

The old SWORD can be repaired, but it's a bit of a PITA because of the epoxy coated parts and riveted standoffs. I've got 4 in need of repair in my inventory, but haven't touched them in years.

[TedBobo]

This is one of the easy E31 jobs I think. Took me about 20 minutes.

Thx Olin...will add this to my retirement "project" list.

[chicosito]

I just ordered my sword for the 8. Hope this solves this issue. My air only works at the highest setting.

[chicosito]

I just installed my new sword today. It took me about an hour, but it was due to re-installing the pesky air duct. Everything else was a breeze.

[dlove]

do you need to remove the glove box to remove the air duct to access the sword ? having trouble getting the glove box out . what am i missing ? thanks in advance !