Guys,

Ive searched and searched and cannot find any info on the R56 relating to a airbag indicator light with horn and steering controls not working. I found some posts for the R53...

I took the airbag off the steering wheel to access the steering controls and clean the wheel. I disconnected the battery and carefully disconnected the 2 connectors and then put everything back as I found it and now the horn & steering wheel controls dont work and the red airbag light is on.

I checked the fuses and connections and all is normal.

Some of the related posts for R53s mentioned the slip ring breaking.

http://www.ebay.com/itm/BMW-MINI-Airbag-Slip-Ring-StalkS-With-OBC-R56-R57-R55-/221656299682?hash=item339bbeb8a2&vxp=mtr
Anyone have any experience fixing this issue on an R56?

 

The slip ring can be rotated 2.5 turns on the left or on the right. When you removed the wheel, did you rotate the slip ring? Slip ring is the one which 2 connecters are connected and can be rotated. Normally after disconnecting the cables you will have airbag error, but i don't know about horn. You have to use a software to clean the errors, and hopefully to make horn work again.

 

yes I did rotate it but I doubt more than one 360 degree turn.

Im gonna see if clearing the airbag error gets the horn working again.

 

ok, so I new I heard something snap when I drove my car after putting the steering wheel back on. Now I know why.

Part of the steering angle sensor and cluster with stalks includes the "volute spring cassette". Its basically a ribbon cable which spins around back and forth as the steering wheel turns left and right and connects to the horn and airbag. But it has limited length so you cannot keep turning it without it snapping, which is why the front wheel have to be straight when you take the unit apart and then you cannot turn the cassette at all until the steering wheel is back on the car. The steering rack then prevent you turning the cassette more than 2.5 turns, lock to lock, and prevent snapping the ribbon connection.

Here is the front of the cassette:





If you spin this, like I did (AND SHOULD NOT HAVE), and dont place it back to its exact center position before putting the steering wheel back on, you will snap the ribbon.

Here are the 2 sides of the volute spring cassette after I took it apart and the end of the ribbon which was pulled from its connection:



The ribbon attached to this white plastic part which sites in the base of the cassette and has a small circuit board which routes to the front of the black disc to where you plug in the airbag and horn switch.



The ribbon is sandwiched inside of this white plastic piece.



The white plastic piece sits inside the bottom of the cassette like so: (normally youd see the ribbon cable entering from the left...)



Here is the end of the ribbon which came unattached.



The ribbon is supposed to sit in there like so. I actually exposed new sections of copper and tried to solder it but I only had soldering wire not paste. Plus I need a fine point solder pen. Point being, you can actually repair this. Despite what the manual states. You just need a lot of patience. It better than having to spend $400-600 on the entire SZL cluster because Mini does not sell the volute spring cassette like BMW does for some of its cars.



Im on the fence about even trying to fix this because this isnt the cause of the DSC light. The DSC error might require an entire new SZL which comes with a new volute spring cassette anyway.

 

Update:

Installed a new SZL, which allowed the horn to work, airbag error light to turn off, wipers stopped turning on for no reason but turn signals still wouldn't turn off automatically after a turn (Makes sense because computer didn't know which direction front wheels were facing). Yellow DSC! and Brake error light were still on of course because the unit hadn't been programmed.

I brought the car into an aftermarket shop that specializes in BMW and Mercedes and they had an OTC brand J-2534 capable programmer (something like this I suppose ) and they programmed the new SZL and calibrated the steering wheel position.

My DSC! and BRAKE light are now "gone". Cost me $112 for reprogramming.

So, I still don't know why I couldn't get the Auto Enginuity software to calibrate the steering angle in the original SZL (before I broke the volute spring). Was it because the old SZL had to be programmed again before being calibrated? I don't know.

All in all it was $400 for part+ $112 for reprogramming.

 

Repairing ribbon cable is tough. You need to expose the bare copper of each run, then probably lap solder each run(wire). Then you need to seal it up so nothing shorts together. It also needs to be strong enough to take the movement, but flexible to allow the movement.

I've repaired several ribbon cables, but they were always in stationary positions once installed. for something dynamic like this, you may just have to bite the bullet.

One thought, if you can source a new BMW part you may be able to scrounge the ribbon cable intact. I'd probably check a MINI wrecking yard for the part you need.

Post up your results. This is one someone else will search for sometime.

 

Amen bro. I tried. I soldered everything as best I could, and verified continuity, but it didn't work when I installed it into the car.

Two things...first I didn't have an example of an unbroken unit to look at for reference. So while the logic of the connections and how they were made seemed obvious, it may not be obvious once its broken. Also, I couldn't tell if one little metal bridge was broken or supposed to be like that. I didn't connect it with more solder and perhaps that was the cause.

Second, this is connected to your steering wheel airbag...and that's about the last thing I want malfunctioning...so I tried to fix it for the fun of it and curiousity of it, but I wouldnt have actually used it.

On the other hand , if you break the ribbon AND you can get your hands on a failed SZL with a good ribbon, its easy to R&R the ribbon (cassette). I tried to find one, but had no luck. I assume the ribbon has to be from the exact same model SZL unit which makes it even harder to find. But maybe not. Maybe any ribbon/cassette from a r56 would suffice.

 

Here is my attempt to repair the ribbon. Looks horrible but had continuity at each pin to end of ribbon with no cross continuity.






I know of at least 2 firms that repairs electrical harnesses. I'm sure they could fix that in a minute. but it would probably cost $100 plus shipping. Which is worthwhile if you know the SZL is otherwise working.

http://www.aeromotive.us/

http://wireharnessrepair.com/

 

Hats off to you for even attempting it.
Many more props for posting the pics of what's in there.

I agree. A face full of unwanted airbag would not be nice. That alone can justify the cost. Now, if it were the passenger's airbag...

 

Thanks hommie.

I guess at the very least folks know what the connection looks like and why the front wheel must be pointed straight ahead and the SZL locked in position with tape or whatever so it doesn't rotate before the steering wheel is put back on. If it does rotate and you don't center it again, the ribbon will snap once you've made a hard turn.