Two months ago I bought a 2002 MCS. 49K miles, all stock. Every 10 days or so, fuse 39, 5amp blows. Power steering goes bye bye. I bought a Bently manual, a more worthless manual I have never seen!

I have been searching threads about PS issues, I can't find HOW the system is supposed to work! It seems that there are 247 fuses that are labelled for the power steering.

Does anyone have a description of how it operates and a schematic?

 

it appears to that fuse 39 is both tied into the alternator and the power steering circuit and runs through the large round connector on the drivers side by the motor mount. so either you got an intermitten short in the wiring or one of the components is in internally shorting and after a period of time blows the fuse.

 

That diagram is prettier than what is in the Bently manual, but it still does not give the whole picture. IT IS stated that the PSP gets power from the 100 amp fuse under the fuse block. F39 is somehow involved in the control circuitry. Somewhere there must be a complete diagram!

 

how do you know it's not the altinator circuit blowing the fuse?

 

also see if your psfan is stuck or sticking .

 

the fuse provides power to the switching transistor inside the pump. also from what i find the 100 amp fuse is just the supplier to the main fuses and the pump rins off a 30 amp fuse.

another diagram attached.

 

The cooling fan spins freely (Oh and I did put on a Moss skidplate to protect it all) . I am sure that fuse "has something to do" with switching, but I don't know what! There could be a wire shorting, a relay sticking or a transiter failing---somewhere in the circuit. I have called 3 local MINI dealers, only to be blown off prior to even reaching anybody. In my hunt for threads and info I found all the cases of spontaneous engine fires traced to power steering...

I am thinking that the Bentley might prove useful to keep the car from rolling while jacked up.

 

The electronic circuit that controls the motor is inside the pump assembly. That's why you can't find any more information on it. The schematic would have to come from ZF but I doubt that information is available.
If you have some experience taking DC motors apart and re-assembling them without causing damage, I would recommend that you take the pump apart and blow the brush dust out of the electronics area inside the pump. It sounds like the brush dust may be causing an intermittent short.

 

I can work on any electronic circuit--but it really is nice to know how it is supposed to work!

That 5amp fuse is NOT supplying the PSP. I could be supplying the cooling fan(s) or not. Or turning on a switching transister. It is somehow communicating with the PSP, however, elsewise the pump would be going down with the fuse.

Yesterday the steering failed without that fuse blowing. And then it came back when I restarted the car. @#$%! THEN, the fuse for the instruments blew.

 

Come on, tiger, if you don't need ABS, surely you can get along without power steering.
(sorry to hear about the troubles - sounds like it's time to replace the PS unit.)

 

I suppose I asked for that one.

The older I become, the stronger my "Inner Luddite" gets!

 

Welcome to the '02 owners club! The '02 MCS uses some strange circuitry compared to newer MINI's. Most likely, your power steering fan is seized, causing an amp overload, and thus popping the fuse. Also, there is probably a Service Bulletin to retrofit the new wiring harness section into your car, so give your dealership a call.

 

MINIs have power steering? There so light, why bother ... all they do is "whine"

 

That comes from a person that's obviously never driven a de-powered-steering MINI!

 

True dat

 

I didn't have any fuse problems but my power steering went intermittent. Sometimes it would come back when the car was restarted. Changing the pump cured the problem.
If you want to disassemble the pump, the most challenging part will be disconnecting the wires that go from the electronics to the brush holders. They are welded to the brush holder. I was able to break the welds. I gripped the wire with a pair of Microshears and twisted the wire sideways. You can't access the electronics without doing this because there are screws inside that hold the circuit to the pump housing.

 

Strange?, possibly, poorly documented?, absolutely! I wish it was as simple as a siezed fan. It spins freely when accessed from below. T'were it that I would replace it with a fan from any one of a million excess microtowers! I am left pondering what is overloading a circuit without knowing just what said circuit is! :impatient

If I can cadge some time on my neighbor's lift next weekend (for the record folks; locate your business next an auto repair shop and you become very lazy about getting your hands dirty! I have a very complete tool box-gathering dust).

After I bought this, a friend was needling me with comments like, "Welcome to Lucas electrical componants". I riposted, in a smarmy way citing Bosch astadt! The universe just loves to humble pride where ever it may surface!

 

looks like that pumps gotta go .

 

After months of the problem having disappeared, it has come back--with a vengence! I finally conceded that the PS pump may just have failed. I changed it. And I replaced that god damned 5 amp fuse with a circuit breaker.

I have since downloaded a more complete set of schematics....which don't actually consider that little fan worth documenting (or perhaps it is labelled as a windshield washer motor..or something). I am learning to HATE BMW's concept of support.

AND THAT DAMN 5 AMP FUSE BLOWS EVERY SINGLE TIME THAT I HIT CITY TRAFFIC! And with it, power steering also goes away.....and then moment later, the electrical system goes into discharge.... I know, from putting a meter in series with the circuit that it draws over 11 amps before my FLuke meter fuse pops. Perhaps the alternator has gone south...the fan runs until the fuse blows.... Anyone have any other ideas?

 

I had issues with my PS pump and my cooling fans...2002 cooper (non S)....turns out there is a wire harness that needed to be installed to seperate the two circuits.....I have a seperate weather proof fuse holder installed up by my DSC pump...I don't know if all were put in that spot when the work was done.....do you have one installed there? Maybe yours hasn't had that done yet?

 

I'm reading this thread with interest, since my PS went out two days ago, accompanied by a blown #41 fuse (replacing the fuse did not resurrect my PS, unfortunately). I know that doesn't completely relate to tigertiger's problem, but I feel your pain!

 

If you have not had the wiring harness replaced to seperate the circuits, you should do that first!

 

-skip-

 

I will try and determine if the split has been done. I don't see it listed in the sheaf of paper that came with it.

In the 6 months prior the expiration of the warranty it looks like everything else was done!

Sigh

 

Service Advisers at Bay Area dealerships are never able to come to phone. After a week of trying, they do not return telephone calls either. BMW/Mini is not doing a very good job of support!