Root cause insight into the common BMW blower motor resistor failures

This does not count the hazardous issue of the soldering failing, causing hazards to the users of the equipment :-(

Reply to
Leif Neland
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That's why there are exemptions for the military and telecom industry, where it's actually important that stuff work properly.

What I find ironic is that the shorter lifespan of consumer gear caused by the RoHS manufacturing has actually increased the amount of electronics going into landfills, making worse the problem that it was intended to reduce.

--scott

Reply to
Scott Dorsey

Most of the people on the BMW forums think it's one of these.

Reply to
Bimmer Owner

Other people have suggested this also.

Some say the potting is what is causing the stress cracks.

Re-insert without potting, is the "said to be" solution.

One question: If the FSU works without potting, what was the purpose of the potting?

Reply to
Bimmer Owner

Good catch!

Reply to
Bimmer Owner

I will try this morning. (I was away on a trip for the past two days).

PS: Had to look up araldite:

formatting link

Reply to
Bimmer Owner

The red jumper was a hack added by one user to fix the solder cracks, I think.

Reply to
Bimmer Owner

This implies two transistors (although I only found one).

I will dig through the mess again - but I think I was too fat thumbed when I cut it open, and may have destroyed the evidence.

I do have a second FSU (since two failed on me) though ... but I want to try to FIX that one (instead of destroying it).

Reply to
Bimmer Owner

I wasn't sure how to cross reference using that list. For example, it had only one BMW entry (camera module); and it did not have GKR or Sitronic or Valeo brands; nor the keywords FSU, nor FSR; but it did have things titled "blower motor controller), e.g.,

FORD F50F-19E624 heater blower motor controller ('97 L. CONNIE) 1

Reply to
Bimmer Owner

Regarding cost, it seems we can get aftermarket parts for about $100; and the part at the BMW dealership cost about $175.

Regarding repair, some have intimated that unpotting and resoldering is a solution.

If that's true, then that might be a viable "fix".

However, I must ask: If it works without potting, and especially if the potting is what's causing the problem, then what was the original purpose of the potting in the first place?

Reply to
Bimmer Owner

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>> that at least is vaguely useful >

maybe it's similar, maybe it's not. the fact that each of the different unit manufacturers has different internals and that they've changed over time doesn't help you.

Reply to
jim beam

no???? really? are you /sure/ about that??? or doesn't sarcasm work for you???

no, you're doing that.

they're not my modules [again, you're not following the thread] and i wouldn't replace them - i'd pwm the motor instead.

Reply to
jim beam

dude, give up on that already. you'll never get good thermal contact second time around.

Reply to
jim beam

to keep the elements out. and the inquisitive.

Reply to
jim beam

and yet, some say that there can be increased reliability.

btw, if you want /real/ reliability, you wire wrap.

Reply to
jim beam

that's bogus. unless there's been a MAJOR screw-up, potting compounds are carefully matched to the thermal and chemical application - they serve to increase reliability, not degrade it.

Reply to
jim beam

I am aware of that. It looks like it ties the two collectors together. But does it go to the contact that connects to the fuse? The main point is "do the collectors (center pin on transistor) connect to the 12 volt input to the module"?

Thanks, tm

Reply to
tm

On this one subject I have no doubt you have personal experience, unlike most of your posts.

nate

Reply to
Nate Nagel

I've got ask- what was this motor used for?

pumping station? mining equipment steel mill?

Reply to
Cydrome Leader

You could call it a sort of wind tunnel. Now obsolete, in great part due to computer modelling making analysis tools like that less important, and in great part due to computer modelling of the tools making it possible to make less turbulent tunnels.

--scott

Reply to
Scott Dorsey

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