# MK6 multi-function steering wheel control -> JoyConEX -> CarPC - need help with button PCB



## wr3ck (Sep 29, 2010)

Hello there!

I've got a 2003 MK4 GTi. I also have a Windows 8 CarPC with Centrafuse as a front end user interface. Don't mind the shift boot, I need a new one.










So, I picked up a 2011 Jetta TDi steering wheel (couldn’t afford\find a flat bottom) that had only left hand multi-function steering wheel (MFSW) controls. I got a right side MFSW pod on eBay as well as a MK4 airbag harness. This is a great how-to on installing a MK6 wheel into a MK4 and I am going to be following it.

*What I am trying to do is reverse engineer the button PCB inside the MFSW controls where the buttons, LED’s, and resistors are located in order to output the resistive button schematic prior to the CAN bus module (I think this is the small PCB behind the airbag that the left+right cables plug into) to a JoyConEX via USB into my CarPC.*

I found this thread on another forum where it looks like someone has already done this exact thing - but I'm having a hard time getting in contact with him because my account on that forum isn’t verified or something. I'm waiting on a reply from the webmaster I guess. (Even though I've been a member on the Centrafuse forum for a while)

So here’s what the LEFT PCB looks like (front+back)

























I count 6 buttons, 6 LEDs, 13 resistors, and one 6-wire connector. I presume that two of the wires in the connector have to be [+DC Voltage] and [Ground], while at least two of the rest of the wires have to be the resistive circuit, I read in another post that four of the wires are two 3-button resistive circuits, but I have yet to determine anything – this is a preliminary post.
Does anyone know if it is possible to find a wiring diagram or drawing of this circuit? I have not opened the right MFSW pod to compare as of yet. I could not find any information with my Google-Fu on the part numbers on the back of the pods either.

The guy on the other forum was kind of hard to understand, I don’t think English is his first language. I looked up the resistor codes using this website and I came up with 9 different resistors.

64R9 = 64.9 ohm
1001 = 1k ohm
2001 = 2k ohm
3291 = 3.29k ohm
4321 = 4.32k ohm
4751 = 4.75k ohm
5601 = 5.6k ohm
6191 = 6190 ohm
1002 = 10k ohm

I'm assuming that six of these should be assigned to the buttons, and the rest have to do with the LED circuit - but the circuit is very convoluted so I'm having trouble following the traces.

This is what the guy on the other forum stated:



otherguy said:


> I have connected the buttons to a Joycon interface to control Centrafuse.
> What radio do you want to control? Is it Centrafuse?
> 
> What I did was:
> ...


I'm not sure what the heck he is talking about when referring to "replacing 9 resistors" because the values of the resistors on the board don’t match his description. The pin-out is very helpful however, and I could theoretically test this with a 12vdc power supply on my bench and the JoyCon connected to my laptop or something.

Anyone have some ideas, or possibly can get a circuit diagram or something?

Thanks!


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## wr3ck (Sep 29, 2010)

ok! zero interest!

anyway, i made some headway.

pictures of the buttons in my possession with labeled items;


























so i just got done with some testing and i got some results!










using my trusty FLUKE179, i was able to meter out the pins. I was also able to hook it to a bench top power supply and find the LED circuit.

so here goes;

PIN 2 + PIN 6 = buttons D (1.998k ohm), E (3.908k ohm), F (1.001k ohm)
PIN 3 + PIN 6 = buttons A (1.001k ohm), B (3.911k ohm), C (1.996k ohm)

so it seems both circuits use the same resistors for the buttons. i should have labeled one group of the buttons backward, but yeah. i dont know how the VW PCB behind the airbag interprets this, but yeah.

SO - my thought is just to add a single resistor, maybe like a 5k ohm on one of the two circuits - effectively making the D,E,F circuit each value raised by 5k ohm allowing the JOYCON to see the difference in each circuit since all four circuits will be joined. so assuming the RIGHT side buttons are the same as this, 3 of the circuits will get a different resistor value, lets say a 5kohm, a 10kohm, and a 15kohm. that way each circuit of buttons will have different values, and i can program all 12 buttons through the joycon. double press and long press are options too - so i can have 12x3=36 programmable options!

suhweet. 

all thats left is to figure out how to get four wires through the steering wheel - if there arent any extras...

in that other thread about mounting a mk6 on a mk4, there is a picture of the MK4 clock spring connector with the MK6 wheel on and the airbag out. i have a 2003 MK4 gti without steering wheel controls. it looks like there is at least 7 pins for the clock spring. two have got to be for the airbag and two have got to be for the horn. im hoping that my clockspring is the same as the mk4's with the MSFW and there are just empty pins that i can borrow. im not in the mood to fit extra wires inside my clock spring LOL.

*does anyone know how many pins the clock spring of a mk4 without steering wheel controls (3 spoke) has, and how it uses them? a simple wiring schematic would be amazing.*

[Mk4 Golf] Fit A Mk5/mk6 Steering Wheel In A Mk4..... ***definitive Thread*** - D.I.Y Guides and How to Instructions - uk-mkivs


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## kauboi (Nov 3, 2004)

very cool, I'm trying to add a multi function wheel to my van, to hopefully control my aftermarket head unit. If I understand your idea, it's that you plan to re wire your wheel and bypass what would normally go to the chassis computer?


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## wr3ck (Sep 29, 2010)

yes that is correct!

i ended up buying two clock springs and putting a second 5-wire ribbon cable by merging the two units.



req (aka wr3ck) on diyma said:


> sorry for the crappy photos btw.
> 
> ladies and gentlemen. may i present to you the ONLY 10 wire mk4 volkswagen golf, jetta, gti, gli, or passat clock spring.
> 
> ...


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## CerealKiler (May 10, 2011)

Truly wish I knew what all was going on with the electronics here.... But this is awesome and I really look forward to seeing the end result and maybe even some kits for you to sell  Could make some good money!


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## Bassboyz (Feb 15, 2010)

This is brilliant Work.....

I recently fitted a MK6 Gti Steering wheel in my Mk1 GT so there's no plugs on the steering column for any connections whatsoever for the steering controls. 
I initially just wanted it for the good looks....
The air bag was already blown, so I had the leather piece professionally replaced without the airbag.
I also have a fully integrated "stripped and modded" Laptop with an external creative audio sound card to run the audio.
However I still want to get the controls working in a wireless application for the windows 7 operating system.
I have a cheapie PC remote control (battery operated) which has a usb infra red receiver and I am in the process of modding the steering control pin outs to the pin outs on the remote control which hopefully will be fitted in the airbag location.
I'm pretty sure I can at least 10 buttons working from the 12 on the steering wheel. The main features I would use are up and down for volume and a mute button. The others will work but I doubt they will be in use often.

I just have a question in regard to the illumination for those buttons. 
I don't have any power coming to the steering(MK1 steering column).
I thought about using the hooter wiring for illumination, but sadly the MK6 steering is way different to the column and the hooter pin does not touch the steering....I will do more work on this to see what can be done.... 
Any other ideas on what can I do to get them lit up when turn on the park lights ? What voltage do those LEDs work on ?


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## wr3ck (Sep 29, 2010)

Bassboyz said:


> This is brilliant Work.....


Thank you very much  



Bassboyz said:


> I recently fitted a MK6 Gti Steering wheel in my Mk1 GT so there's no plugs on the steering column for any connections whatsoever for the steering controls.


Its good to know the spline for the mk1 is the same as the mk6. Thank you for that! I just bought a mk2 so I may be doing something like what you are trying in the near future.



Bassboyz said:


> I initially just wanted it for the good looks....
> The air bag was already blown, so I had the leather piece professionally replaced without the airbag.
> I also have a fully integrated "stripped and modded" Laptop with an external creative audio sound card to run the audio.
> However I still want to get the controls working in a wireless application for the windows 7 operating system.
> I have a cheapie PC remote control (battery operated) which has a usb infra red receiver and I am in the process of modding the steering control pin outs to the pin outs on the remote control which hopefully will be fitted in the airbag location.


I think my first idea would have been to find a RF based remote rather than an IR one. That way you wouldn't need the led to be aiming at a sensing diode. I'm not sure how the circuit board is designed for your remote though. I do know the circuit for the left set of buttons is resistive based and there are two circuits each with three buttons. Both circuits have the same set of three different resistors in there. There are three pins on the back that correspond to the two circuits. A common ground pin for both circuits and two separate signal wires. The way the car tells the difference between the circuit is what pin the input was plus the resistor. I don't know why they did it that way instead of one circuit with two pins and six different resistors but I guess they get paid the big bucks.



Bassboyz said:


> I'm pretty sure I can at least 10 buttons working from the 12 on the steering wheel. The main features I would use are up and down for volume and a mute button. The others will work but I doubt they will be in use often.


I use next/previous track for left/right. Volume up/down for up down. Play/pause for the middle button. Windows desktop for the long skinny button on the bottom.I found that mute was the same for play/pause in my expierence.



Bassboyz said:


> I just have a question in regard to the illumination for those buttons.
> I don't have any power coming to the steering(MK1 steering column).
> I thought about using the hooter wiring for illumination, but sadly the MK6 steering is way different to the column and the hooter pin does not touch the steering....I will do more work on this to see what can be done....
> Any other ideas on what can I do to get them lit up when turn on the park lights ? What voltage do those LEDs work on ?


The led circuit runs on 12v as you can see in the picture above of them lit up on top of the power supply. The big LCD below that says 12 is the voltage I had it set to. I would say use the horn power but you had already thought of that and it is not a viable idea as it does not run through the column. A battery pack may be an easy way to do it. You will need batteries to power the infra red remote, why not put a 12v battery in to power the lights? You may have to put a reciever of some kind in the airbag housing and a transmitter that is tied into the airbag switch that will close the circuit for the led illumination.

Also you may want to find a clock spring from a mk6 and see about trying to retrofit it into the column. That would give you an option to hardwire the lights and controls to a JOYcon exactly like I did. But I don't know what kind of room there is behind the steering wheel. If you want to pm me I can give you my contact information so it is easier to chat about things.


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## Bassboyz (Feb 15, 2010)

Hi Wr3ck

Thanks for your reply....

Some background info...Not sure where you are located......In South Africa we still had the MK1 Golf produced until 2011 (If I remember the year correctly). They were kitted out with some upgrades eg. a full driver and passenger window (without quarter glass).
They also had new type of steering wheels and completely new dashboards - Google Golf MK1 velociti and check them out. There was even a "R" line model 1.8i . It had a beautiful body kit.
So these steering columns had an adaptor spline that fitted over the small original spline (the small spline is also different to the old mk1). I used one of these but it was not a straight fit. Had to be modded.
So just to clarify, the splines are vastly different and not compatible at all.

Also thought about using the Golf MK6 clock spring for the rear of the steering but I don't have the space and it will end up complicating things.
My other idea is to use the original mk1 steering back ring and fabricate it to the rear of the MK6 steering....single pin is fine. I just need to reroute the hooter wiring for illumination. It hopefully "should" work. 

I have made some headway on this project but encountered a few challenges.
The 6 pinned buttons strangely have some sort of resistance and they do not work like a simple on and off switch. I verified this by removing them off the board and testing. Very weird indeed.
So I ripped open an old JVC radio face which has similar buttons but easy 2 pin config.
I am in the process of replacing the buttons completely. Also the config on the remote cannot allow for a common ground so it will be an independent connection.
The IR remote works great....you don't really need to point it directly to the receiver, it also has a long range so the transmitting and receiving is good.
I thought about this before I started....Most people use the steering controls when the steering is straightened anyways.....I have never seen someone using it whilst turning !! LOL 
So pointed the IR transmitter one direction should work out perfectly.

I will send you a PM as well with my details...we will chat further...

Cheers for now...


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## esilviu (Nov 1, 2006)

Hi Wr3ck,

Did you finally succeed to install also the right buttons ?

Could you please post pictures with both sides of the right buttons board too, to see if we can make a drawing of the circuit in order to find a solution for connecting to RCJoycon EXR together with the left buttons board.

Did you tried solution pointed out by Unrealistic guy for the right buttons board, even it's more preferable to add 2 resistors instead of replacing 6 resistors ?

Thanks in advance.


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## esilviu (Nov 1, 2006)

I read the entire thread on diymobileaudio.com , but you didn't mention clearly how you succeeded make it work for left buttons board, did you add resistors or did you remove and replace them, what was the final value for each button when pressed, because it was not very clear how you proceeded at the end from your thread?
Thanks very much


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## wr3ck (Sep 29, 2010)

thanks for your interest in the project. ill have to go back over my notes on the whole thing, but I just picked an arbitrary number of resistor value. 

for the left side, the resistors work in two groups of three, or six total buttons. if you are looking at the face of the buttons, they are as follows.

BUTTON SET 1 = 1. VOLUME UP, 2. PHONE, 3. VOLUME DOWN
BUTTON SET 2 = 1. LEFT ARROW, 2. MICROPHONE, 3. RIGHT ARROW

I cannot remember off the top of my head what values and pins they are, like I said ill have to check my notes - but basically there are three pins that this circuit uses. there is a common ground, and a pin for button set 1 and a pin for button set 2. the car knows what button you've pressed because

PIN1+BUTTON2=PHONE
PIN2+BUTTON3=RIGHT ARROW

I hope that makes sense. but since we are using a resistive based steering wheel control system we need to make sure that each value of resistor for the button is different. if we link PIN1 and PIN2 together then we need to differentiate the values by adding an arbitrary resistor to offset one of the button sets from each other. something like a 1000ohm resistor will offset it. just put it in line with PIN2 and you'll be good.

but that only gets us the LEFT button group working. the right button group is DIFFERENT than the left and I hurt my brain. for some reason, they've included a 16ohm overall resistance to the circuit (the same as above, two button sets, three pins) but the circuit is always closed with a 16ohm value. if we try and put a resistor on each pin here (lets say 1300ohms and 1700ohms, again numbers I just made up) then the aftermarket resistor sense in your headunit will always see the lowest closed circuit resistance and think you are holding a button down all the time, that sucks. so I bypassed the 16ohm resistor and then it was just a CLOSED circuit with 0ohms. that's no good, we need it to be an OPEN circuit so when we depress a button the circuit will be the resistance linked to that button for the period of time the button is depressed. I then REMOVED the resistor and nothing worked at all. the traces on the board are multiple layers (front+back) and I had a hard time tracing it around the board. 

so I have not gotten the right side figured out yet. I will eventually, but at the moment I just covered the right buttons with a blank-off plate from the TDi wheel haha.

however, there is a new part from JoyCon that interprets canbus data. all you've gotta do is plug the buttons together like theyre supposed to be, supply +12v to the canbus analog to digital converter box that's in the bottom middle of the steering wheel, and find the canbus output data lines, then plug them into the new JoyCon and it should take care of the rest. but I have not tried this yet.

http://www.rcjoycon.com/base_3/menu...e1=&com_board_search_value2=&com_board_page=&





I hope I answered your questions a little bit. ill see if I can make some time to figure it out soon!


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## esilviu (Nov 1, 2006)

Thanks , so practically if we buy the canbus rcjoycon version we will be able to avoid the pain of adding or removing the resistors and detecting trace of the left and right buttons circuits.

Could anyone who already tested this variant - Canbus RCJoycon version connected to the module inside Golf6 MFSW powered with 12V - confirm that all the 12 buttons are detected and working fine with a CarPC?


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## wr3ck (Sep 29, 2010)

I plan on testing this in a friends car soon. ill update this when I am able to buy the joycon with canbus - however, it will only output via USB. it wont take in canbus and output a resistive loop for aftermarket headunits I don't think. plus, I am not sure if it will understand the MK6 VW canbus radio codes as they don't seem to be on the list of things that the joycon can interpret so it is a long shot right now.



rcjoycon.com said:


> *CPJexc(CarPc Joycon Exc) converts CAN, IBUS, resistive, digital steering wheel controls into USB keyboard and HID remote controller.*
> 
> - Converts CAN, IBUS, resistive and digital steering wheel controls *into USB *HID keyboard
> and HID remote controller
> ...


http://www.rcjoycon.com/base_3/menu_10.php?com_board_basic=read_form&menu=10&com_board_idx=27


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## wr3ck (Sep 29, 2010)

for anyone whom is interested,

the owner of RC joycon got back to me



Kang HoRyong said:


> I wish I could make JoyCon hear the 2012 LIN data.
> 
> I will try to do it.
> 
> ...


so that's a big ol' fat no. if anyone wants to pull the MSFW data from the MK5,6, or 7 - this isn't going to be a feasible solution.

I have been working on designing a new resistive PCB to replace the one in my MK7 steering wheel. im learning how to design a PCB at the moment. :banghead:


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## Rod Ratio (Jun 6, 2012)

Subd


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## Low_Mk4 (Jul 12, 2018)

What head unit is this?









Sent from my ONEPLUS A6013 using Tapatalk


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## wr3ck (Sep 29, 2010)

Low_Mk4 said:


> What head unit is this?[/IMG]
> 
> Sent from my ONEPLUS A6013 using Tapatalk


Hello, sir.

That is a custom made windows carPC. I made it from scratch basically. here is some information if you're brave 

www.instagram.com/R4N63R

https://www.diymobileaudio.com/foru...orum/127629-first-foray-into-carpc-realm.html


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## sxtuning (Apr 27, 2021)

wr3ck said:


> ok! zero interest!
> 
> anyway, i made some headway.
> 
> ...


hello there can you shiw me the pins thats illuminate the buttons ?
are they work ok 12v


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