re: [bmw] Speaking of seats

[Dave <dafunn@xxxxxxxxxxxxx>]

> Date: Wed, 26 Nov 2003 18:46:59 -0800
> From: "Barton Clark" <BClark@domain.elided>
> Subject: [bmw] Speaking of seats

[snip]

> And on another topic, I noticed yesterday that the (heater/air) blower motor
> in the dash was making a high pitched squealing sound, and today, it seems to
> have mostly failed. I say mostly becuase, if I rotate the dail completely
> clockwise until it hits its limit switch ( I can hear the contact being made)
> the fan WILL come on full blast. It just no longer comes on at any
> intermediate speed. Does anyone have any advice on where to start? (I figure
> I'll start by checking out the fuse box tomorrow, though I find it hard to
> believe that there would be two seperate fuses for the adjustable low speed vs
> the high speed, full-on mode).

I can tell you right now it won't be a fuse.  That blower motor is about to
die, but you might get away with just cleaning it and bringing it back to
life for a while longer.  The key symptom here is the high pitched squealing
sound, followed by the intermittent usability.  I've seen these same symptoms
about a half a dozen times now in my cars and the cars of my friends.

Pull out the blower motor if you can (I'm not sure how to do this on a
6 series, but on the 3 series it was pretty straightforward) and clean the
crap (literally) out of the motor.  I personally use WD-40, but you could
probably also use some electrical safe commercial cleaners to get inside it.
You should notice a large amount of grease and gunk coming out with the cleaner
as you're spraying it - this is a good sign as it means you've found the
problem.

Looking from outside the motor, you *should* be able to see the windings
inside.  Aim the cleaner at those.  I'm guessing based on what I've seen, but it
looks like the windings inside the motor are getting dirty and gunked up and
having trouble building up that magic electromagnetic field that makes the thing
turn.  Put enough current through it (i.e. - turn it on high) and you can burn
through to make it work.  Clean off the windings and you can (usually) bring it
back to life completely, if only temporarily.

I'd be curious to hear what others think would be the best cleaner for
this situation - I'm sure WD-40 is less than optimal, but it's the only
thing I've ever used.  I've only seen one situation where it wasn't the
last step, but it brought the motor back to life for a few months before
the squealing noise started again (and my friend still hasn't replaced the
motor, but it's his car, not mine :).

--Dave
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