Root cause insight into the common BMW blower motor resistorfailures

"Bimmer Owner" wrote in message ...

On Tue, 26 Mar 2013 09:43:58 -0700, wrote:

> They do have that 16 pin chip there, doing something.
> It might receive the command and then output the appropriate PWM for
> rest of the circuit.

Someone had scoped the whole board, and it was DC voltage everywhere
(according to that reference). It's pretty clear there is no PWM.

The 16-pin surface mount chip seems to be a automotive temperature
compensated voltage regulator with a huge voltage range, according
to a lookup of the part number on it.

Here is the Elmos 10901D chip of my FSU as I cut it open today.
http://www4.picturepush.com/photo/a/...g/12515632.jpg

I wish there was a way to get rid of that heavy fibrous plastic goop!
(What is that black fibrous tough stuff anyway?)

I have had good luck removing the stuff used on motorcycle voltage
regulators that were potted soaking in MEK Methyl ethyl ketone
(spelling?). Potent stuff. Use outdoors and keep your hands out of it. WW