Root cause insight into the common BMW blower motor resistorfailures

[Bimmer Owner]

If you google for 10901D it comes back with hits to Chinese chip brokers
that show it as an Elmos 16 pin surface mount chip.

I found a Russian language description of it here:
http://tinyurl.com/crg2sms
http://kazus.ru/schematics/electric...%DF%D2%CE%D0%20ELMOS%2010901D&nohistory=1&h=1

 

[Bimmer Owner]

I found a Russian language description of it here:
http://tinyurl.com/crg2sms

Here is a google translation

REGULATOR ELMOS 10901D
Car Voltage Regulator
Category: Car
Source: Radioland country Electronics
Temperature controller cabin air KAMAZ

Source: Plans radiokonstruktsy
Simple Temperature compensated voltage regulator.
Controller together with thyristor-transistor electronic ignition unit
with a long spark, ensuring the rapid start-ups at various operating
conditions, allowed to increase battery life of up to nine years.

Source: For the life of a soldering iron ...
Regulator for automotive windshield

Source: MASTER KIT
The controller measures the wiper-this control is designed to use regular mode switch blades and is contactless.

Source: For the life of a soldering iron ...
Temperature compensated voltage regulator device in some ways superior designs.
The controller can be used as a universal device is suitable not only for
mounting on any car, but everywhere, where the generator rotor speed is
variable (eg, wind power).
Choose the appropriate control elements, it can be easily adapted to work
with any voltage (up to 400V) and excitation current (tens of amperes).

Source: For the life of a soldering iron ...
Voltage regulator 2012.3702, 22.3702, 221.3702

Source: For the life of a soldering iron ...
Voltage regulator 201.3702

Source: For the life of a soldering iron ...
Voltage Regulator 13.3702

Source: For the life of a soldering iron ...
Voltage regulator RR132A, 1112.3702

 

[Bimmer Owner]

I found a Russian language description of it here:

Googling for the Russian text, I find they appear to have
the same problem with the same FSU over here:
http://www.elektroda.pl/rtvforum/viewtopic.php?p=8838466#8838466

 

[jim beam]

Here is a google translation

REGULATOR ELMOS 10901D
Car Voltage Regulator
Category: Car
Source: Radioland country Electronics
Temperature controller cabin air KAMAZ

Source: Plans radiokonstruktsy
Simple Temperature compensated voltage regulator.
Controller together with thyristor-transistor electronic ignition unit
with a long spark, ensuring the rapid start-ups at various operating
conditions, allowed to increase battery life of up to nine years.

Source: For the life of a soldering iron ...
Regulator for automotive windshield

Source: MASTER KIT
The controller measures the wiper-this control is designed to use regular mode switch blades and is contactless.

Source: For the life of a soldering iron ...
Temperature compensated voltage regulator device in some ways superior designs.
The controller can be used as a universal device is suitable not only for
mounting on any car, but everywhere, where the generator rotor speed is
variable (eg, wind power).
Choose the appropriate control elements, it can be easily adapted to work
with any voltage (up to 400V) and excitation current (tens of amperes).

Source: For the life of a soldering iron ...
Voltage regulator 2012.3702, 22.3702, 221.3702

Source: For the life of a soldering iron ...
Voltage regulator 201.3702

Source: For the life of a soldering iron ...
Voltage Regulator 13.3702

Source: For the life of a soldering iron ...
Voltage regulator RR132A, 1112.3702

you don't need to know this stuff any more than you need to know the gas
excitation voltage in a broken fluorescent tube. because you're not
going to unpot the thing and replace the chip. because it's probably
not the chip in the first place.

not trying to be rude - just trying to get you focused on the relevant
stuff - that the two options are:

1. continue replacing the existing [under-rated, low tech] unit.
2. build and deploy a pwm unit instead.

#1 is really not /that/ expensive, particularly if you factor in time,
even if it is part of the bmw marketing susceptibility tax.

#2 is a much better time investment - it certainly has a much better
return than figuring out that the existing unit is not repairable later
rather than sooner.

 

[jim beam]

That's an interesting idea.
http://www3.picturepush.com/photo/a/12475041/img/12475041.jpg

The fuse for the blower motor is called the "infamous F76" for a reason.
http://bimmerfest.com/forums/showthread.php?t=674612

It's a 40 amp fuse

you don't want to try and use a 10/20A meter in the slot of a 40A fuse.
you probably already know that, but just saying.

 

[andrew s]

jim beam wrote on Fri, 22 Mar 2013 07:04:19 -0700:

#1 is really not /that/ expensive, particularly if you factor in time,
even if it is part of the bmw marketing susceptibility tax.

I don't know how many bmws are out there, but let's say it's a million
and then multiply that million by 100 dollars, and then let's see how
much it is in terms of expense.

 

[[email protected]]

This is an interesting approach, given that the vast majority of
bimmer owners do NOT replace the blower motor - they replace the FSU.

While the blower motor replacement procedure is a major PITA, one
'can' test the leads from the FSU harness connector pins #5 and #1
which are power and ground respectively to the blower motor.

Again, we don't have a circuit diagram, but it has been said that
the blower motor takes about 6 amps (variously, depending on the speed)
but it would take a test jig to test that in operation.

To my knowledge, nobody has created that test jig (although I know
of only one attempt, which failed):http://www.bimmerfest.com/forums/showthread.php?t=678534&highlight=fsu

It's easy enough to test the resistance of the blower motor though,
and those results have come out at about 0.4 to 0.6 ohms.

It would be expensive to change a blower motor on a whim, so, how
would YOU suggest the blower motor be tested in situ?

If it's just a typical DC motor with two leads, apply 12V and
it should run full speed. You could also measure how many amps it
draws when running. That is, IF it's just an ordinary motor.

 

[[email protected]]

That's an interesting idea.
http://www3.picturepush.com/photo/a/12475041/img/12475041.jpg

The fuse for the blower motor is called the "infamous F76" for a reason.
http://bimmerfest.com/forums/showthread.php?t=674612

It's a 40 amp fuse under the glovebox but it's in a really inaccessible
spot; however, it's right side up, so, the wires going INTO it are
visible from the tips of your feet under the glove box.

So that's a possibility; but you'd have to cut the wires.
http://www5.picturepush.com/photo/a/12475043/img/12475043.jpg

Why would you have to cut the wires????
Simply remove the fuse and connect the ammeter. You guys make your
lives so difficult

 

[[email protected]]

  Why would you have to cut the wires????
Simply remove the fuse and connect the ammeter.  You guys make your
lives so difficult- Hide quoted text -

- Show quoted text -

It's kind of amazing the fuse is 40 amps, no? I mean a 1 hp
motor draws ~1500W And this heater blower is 480W?
Seems like a lot to me.....

 

[jim beam]

It's kind of amazing the fuse is 40 amps, no? I mean a 1 hp
motor draws ~1500W And this heater blower is 480W?
Seems like a lot to me.....

in this thread it's been said it draws 6A running. x 12V, that's 72W.

but the reason you have 40A is you have very high current start-up
transients. on a cold day with a gale blowing outside the car, and some
snow in the system, you could be into the 30's without too much problem.
so you need an amperage that will still blow in the event of short
circuit, but which will tolerate the above.

 

[Clive]

In message

Instead of just a simple
fan motor, it's a fan that's variable speed, driven by a PWM
signal.

If by PWM you mean pulse width modulation, then it would allow for
variable speed, but a DC motor is an inductive load and is not sensibly
controlled by such a system unless there is something in the circuit to
allow the peak voltage generated by the motor at pulse cut of to be
shunted to earth.

 

[[email protected]]

In message


If by PWM you mean pulse width modulation, then it would allow for
variable speed, but a DC motor is an inductive load and is not sensibly
controlled by such a system unless there is something in the circuit to
allow the peak voltage generated by the motor at pulse cut of to be
shunted to earth.

That "something" could be as simple as a diode. PWM is
commonly used to vary the power to a motor. BMW, for
example, uses it on the aux fan motor of the X5. And I
would suspect that it's also used for the blower motor
because you wind up wasting a lot less power that way.
And every little bit of power saved adds up and effects MPG.

 

[[email protected]]

Have you got a link to these "common problems" you keep posting about?




- Show quoted text -

I don't have a link, but we had the blower resistor widget
go on an X5 here. And the aux cooling fan motor has gone
twice. There are plenty of threads online about many people having
those problems. Oh, and don't forget the
nice X5 feature where the cable that they use to hold up the
windows snaps, sending the window crashing down inside
the door, breaking it into a million pieces. Had that happen
twice too, once while the car was just sitting in the driveway.
Other time was driving down the highway.

Then there are their defective rubber parts. Like the boot on
the intake manifold that cracks in just a few years. Or the
CV joint boots. I've had lots of cars with CV boots and
only on the X5 do they fail every 20K miles. I've seen Honda CRVs
that went 200K miles with no failure.

 

[Clive]

In message

That "something" could be as simple as a diode. PWM is
commonly used to vary the power to a motor. BMW, for
example, uses it on the aux fan motor of the X5. And I
would suspect that it's also used for the blower motor
because you wind up wasting a lot less power that way.
And every little bit of power saved adds up and effects MPG.

I agree with all you say.

 

[jim beam]

Nothing wrong with linear motor control, it's just inefficient and
produces a lot of heat. I used to work in a place with a 1.2 MW DC
motor

that must have been interesting - what did that motor do?

whose field coil voltage was controlled by a couple rooms full
of cast-iron resistors.

that must have been a sight to see too.

The resistance array lasted nearly 80 years
before the whole facility was taken down.

shipped to china? or replaced by pwm controllers?

 

[jim beam]

In message

If by PWM you mean pulse width modulation, then it would allow for
variable speed, but a DC motor is an inductive load and is not sensibly
controlled by such a system unless there is something in the circuit to
allow the peak voltage generated by the motor at pulse cut of to be
shunted to earth.

ancient news - controller designers and semiconductor manufacturers have
been on top of this from day 1.

 

[jim beam]

I don't have a link, but we had the blower resistor widget
go on an X5 here. And the aux cooling fan motor has gone
twice. There are plenty of threads online about many people having
those problems. Oh, and don't forget the
nice X5 feature where the cable that they use to hold up the
windows snaps, sending the window crashing down inside
the door, breaking it into a million pieces. Had that happen
twice too, once while the car was just sitting in the driveway.
Other time was driving down the highway.

Then there are their defective rubber parts. Like the boot on
the intake manifold that cracks in just a few years. Or the
CV joint boots. I've had lots of cars with CV boots and
only on the X5 do they fail every 20K miles. I've seen Honda CRVs
that went 200K miles with no failure.

serious question - why did you buy it?

 

[Clive]

It's easy enough to test the resistance of the blower motor though,
and those results have come out at about 0.4 to 0.6 ohms.

Motors are not just a resistive load though.

 

[[email protected]]

In message

If by PWM you mean pulse width modulation, then it would allow for
variable speed, but a DC motor is an inductive load and is not sensibly
controlled by such a system unless there is something in the circuit to
allow the peak voltage generated by the motor at pulse cut of to be
shunted to earth.

PWM is the most common method of controlling the speed of DC motors -
a flywheel diode is part of the "system" to handle the inductive
kick-back. Virtually all battery operated variable speed power tools
use PWM. So do virtually all electric bicycles with brush motors and
the vast majority of electric forklifts.

In fact, just about any application of a brush type DC motor that
requires reasonable speed control has switched to PWM control of some
sort over the last 20 years, including power wheel chairs (except
those using 3 phase brushless motors)

 

[[email protected]]

Take a blown fuse and use it for a test connector with a cheap
50-0-50A meter. Then you can just plug it in in place of the fuse to
make the test. You won't even have to worry about the polarity. You
can use a high current shunt, & a digital meter if you want more
accuracy.

Or just get the special tester that is made to plug into the
fuseblock. Autel makes the MX101 and 201 (10 amp and 20 amp) units for
the lighter duty stuff.