I have a r56 S. my steering wheel has the phone button on it, but i do not have the blue tooth in the car. is it possible to wire up lets say an air horn compressor to that button?

 

Not easily you would have to hack the computer to do such a thing.

 

Not if you cut stuff and wire directly, although I don't know how it's all put together so that may involve scratching the gold off a circuit board and doing some precise soldering.

 

Those switches are micro-switches meant to send a data signal. They are momentary contact and probably could not sustain any current through the switch. Additionally, there may not be a harness hooked up to them and wiring to the surface mount PCB would be very difficult. I wouldn't want to mess with it.

 

As what Splattj said they will not work unless you have hacked the computer to get the out puts from it or add another item that can decode the correct button press and then make it do something for you. There is only one switch on some cars that i know of that works like a regular toggle switch (on and off) and that is the one for the added driving lights. All teh other toggle switches are momentary contact.

Now if someone were to ask FES Auto to check to see if one of their units were to be able to decode the signal from the switch you may be able to make it turn on lights but again there is a lot of work (engineering) behind doing such a project.

 

I agree it won't be easy but what do we know about the circuit boards in the steering wheel? Are all the buttons completing circuits that get multiplexed locally before being sent to the ecu? Or is the ecu sending seperate signals along a bundle of wires or perhaps a ribbon cable? If it's the latter then I see no reason one couldn't cut the two wires associated with said button in order to run a small current through the button to a relay. This would be pretty simple if you've any experience with wiring. If the situation is the first I mentioned, then hacking would be in order but I would be surprised if that is the case as it's quite a bit more complex for the sake of less wires.

Of course I have no experience with BMWs so I can't really comment on what route they would take as opposed to my previous cars.

 

The wiring diagrams indicate that the output from the steering wheel buttons is a single K-BUS data line.

 

Well damn, they really don't want us modifying stuff do they.

 

rkw, you beat me to it. And your answer was much kinder than mine would have been. One would think that with over 3000 post as I have I might actually know what I am talking about. And that is not to say i have never been wrong because I have but 99% of the time i look things up in the WDS or other resources I have to get the most correct answer I can.

As for another problem that could arise, depending on the switch cluster behind the steering wheel may also not allow for the controls to work as we have found that it is not just plug and play for the steering wheel controls. If you have the wrong switch cluster (SZL module) then even with the steering wheel controls the cruise control and audio controls will not work. And it seems that if you have an automatic then there is a problem with having both MFSW buttons and Shift Paddles per this post. https://www.northamericanmotoring.co...08-post37.html But I had a 2010 loaner recently from the dealer that had paddles shifters and the MFSW and they both worked so there my be another SZL module that can make all of it work.

Now taking a decoder and finding a place to attach to the K-Bus and decode the signal may be possible but that will take some work, probably more than the OP wants to go thru.

To mastawyrm, what seems like it should be easy on these cars ALWAYS turns out to be difficult.

 

I didn't mean to sound like I was calling you out, I was just asking if it was even known which way was used. My Mini's still being shipped so I don't have any firsthand experience here, only standard electronic knowledge.

 

Standard "Old School Electronics" for cars does not apply to the MINI, EVERYTHING is computerized.

 

Apparently so. So do you know how they're combined? I would imagine it's a serial connection similar to the way old keyboards/game controllers used to work. EDIT: nevermind, I see that K-BUS was mentioned
But yeah, you're right it's definitely more work than it's worth for most, too bad the ECU isn't open source. I wonder if the ECU has a triggered output as a response to the button that could be tapped somehow. Probably not for a button like phone control.

 

There are some people working on deciphering the K-Bus, there is a thread around here for it somewhere.

As for the car there are the following

K-Bus
MOST Bus Ring - fiber optic
JBE (junction box electronics - i.e. fuse panel) computer
CCC-ASK - (i.e. radio head unit) that controls many of the OBC functions and radio, speedo, etc.
Footwell Module - controls lighting/window/sunroof etc.

Just to name a few without looking at the schematics again.

 

Oh and DONT EVEN ASK about the freakin' seat belt gong. there are a nubmer of threads and many thousands of hours spent on that with the only success being a "chimex" or belt buckle end.