E39 540I/M5 Steering Wheel Control Retrofit for Dual Stage Airbag Wheels

[TommyMaddox]

I'd like to contribute my notes on successfully retrofitting both E39 540i/M5 Audio and Cruise Control MFL (Multi-Function Steering Wheel) controls into the Dual Stage Airbag Steering Wheels found in facelift and later (99-2002) BMW Z3 models or vehicles with an MS42/MS43/MSS52/MSS54 ECU.

This is not intended for people who don't have electronics expertise. Please don't consider this project if you intend to connect wires with twisting and electrical tape, or butt splice connectors etc... Either solder and heatshrink or alter the pin layout on the factory connectors.

Parts required:

E39 540i/M5 MFL cruise control buttons, featuring the 'speaking man' and I/O button BMW PN 61312490233 and BMW PN 61312695128
E39 540i/M5 cruise control button connector bridge cable (4 pin) BMW PN 61102493715
E38/9 7 Polig (7 pin) clock spring with heated steering wheel tracks BMW PN 32341094262
E38/9 7 Series carbon brush holder dual pin BMW PN 32311091732
Optional: Lower column housing without CC cutout BMW PN 32311093274, note that I've seen cutout versions with the same part number so verify before you buy

Tools/Consumables:

Pin and De-Pin tools
Soldering Iron
Female spade connectors (small)
Heatshrink tubing
Lighter or heat gun
Might need Metric tap and die set for threading ground pin connector hole if you don't have the small screw, or if that hole isn't threaded
Stock ground screw, or slightly larger machine screw corresponding to tapped hole
Might need files to remove casting/flash lines on the connector hole in the wheel to fit the clock spring wiring through.
Wire for connecting to I-Bus line for stock radio, or for connecting with ASWC-1 system for compatibility with aftermarket radios.
Wire for connecting to FGR interface pin 2/Pin 27 of ECU for Cruise Control System
Recommend adding 2/4 pin inline connectors for the carbon brush connectors for easy disconnect/removal when servicing the steering column
Will need to harvest some pins or re-use existing connector wiring as the pin sizes are different between the old and new clock springs, so I recommend solder and heatshrink instead of de-pinning and repinning the main connector

All pins are numbered left to right, however verify all functions for your own application as parts and wiring may vary. Something interesting I noted is that the 6 pin Z3 wheel setup had a pin order change from inside to outside connector. Additionally the wiring colors on the airbag/horn connector for the Z3 6 pin cable change from clockspring side to airbag side. So triple check everything

Stock 6 Pin Z3 Wiring configuration:

Column Side:

1: Airbag: Yellow Black Stripe
2: Airbag: Yellow Brown Stripe
3: Airbag: Grey Black Stripe
4: Airbag: Grey Brown Stripe
5: Horn: Brown Red Stripe
6: Horn: Brown Black Stripe

Wheel Side:

1: Airbag: Yellow with Black Stripe
2: Airbag: Yellow with Brown Stripe
3: Horn: Brown with Red Stripe
4: Horn: Brown with Black Strip
5: Airbag: Grey with Black Stripe
6: Airbag: Grey with Brown Stripe

7 Pin with heated strips stock wiring:

Wheel Side:

1: Red Airbag +
2: White Airbag -
3: Black MFSW
4: Blue MFSW and Horn Gnd lug
5: Gray MFSW
6: Yellow: MFSW
7: Brown: Horn +
8: Large Male Spade: Heat +
9: Small Male Spade: Heat -

Column Side:

1: Red
2: White
3: Black
4: Blue
5: Gray
6: Yellow
7: Brown
8: 2x Brown from carbon brushes (Inside Ring)
9: 2x Green from carbon brushes (Outside Ring)

MFSW Button Unit stock configuration:

1: Black - Ground
2: Gray - Cruise Control
3: White - I-Bus
4: Red - Power

Pin 2 and 3 can be bridged here to gain an extra empty pin on the new clock spring.

Chosen Custom Assignments for this project:

1: MFSW CC Gray (Pin 2 on MFSW connector)
2: Airbag (Pin 1 on Z3 connector)
3: Airbag (Pin 2 on Z3 connector)
4: MFSW I-Bus White Pin (Pin 3 on MFSW connector)
5: MFSW Gnd Black Pin (Pin 1 on MFSW connector)
6: Airbag (Pin 5 on Z3 connector)
7: Airbag (Pin 6 on Z3 connector)
8: Horn - (Small spade) Pin 3 on Z3 connector
9: Horn and MFSW + (Large spade) Pin 4 on Z3 connector

I chose this configuration for a few different reasons. This allows a good signal ground for the MFSW control module, and good power supply through the carbon brushes and copper rings for the MFSW and horn. It retains the Z3 connector plug for the airbag/horn unit which allows easy serviceability. Additionally I ran into issues when trying to share the grounds with the MFSW module and horn, as it would continuously honk because if I recall correctly, the horn circuit is activated when a completion is detected, which was being done by the MFSW button module. Shared positive is okay though.

Additionally the CC and I-Bus signals can be carried on the same line that is split after the wheel to head to the Pin 27 X60004 of ECU and I-Bus line for the radio. This would theoretically allow you an extra data pin to be used for an additional switch, shift lights, paddle shifters, or other devices where you can draw power and ground from the wheel and existing connections.

Procedure:

I highly recommend obtaining and making the wiring changes using a sacrificial 6 pin clock spring to harvest the connector bodies ahead of time so you can bench test functionalities successfully on your modified 7 series slip ring. I opted to make all changes to the 7 series heated steering wheel slip ring so that no wiring changes would be required on the body harness side stock 6 pin steering wheel connector. I added a male and female 3 pin connector to add in the 3 extra pins that were gained with the addition of the new ring. That connector contained the MFSW CC wire, the MFSW I-Bus wire, and the MFSW Module GND wire. It turns out for my situation IBUS and CC have to be bridged to function for some reason.

1. Remove Airbag
2. Remove Steering Wheel and stock slip ring
3. Remove Button pad blanks
4. Install modified 7 series heated wheel slip ring onto wheel
5. Connect and install button pads onto wheel
6. press the carbon pin brush holders into the existing hole for them, note the alignment slot.
7. Route I bus and cruise control connector wires through your vehicle.
8. Disconnect FGR module, optionally tap MFL CC wire into Pin 2 of X10170 (I also used the GND pin of X10170 for the MFSW module GND) or Pin 27 of x60004 on ECU
9. Optionally remove FGR module and stock CC switch
10. Reinstall steering wheel
11. Connect Column side wiring connections (main connector plus the heated pin connectors you hopefully added)
12. Connect and install airbag/horn assembly
13. Test functionality. You can check and clear any airbag issues in INPA, along with verifying cruise control switch operations by going to Engine>YourECU>Status>Digital>FGR.

For the audio buttons to work, connect the I-bus wire to your existing white and yellow stripe I-Bus line or to your aftermarket wheel control module (I recommend ASWC-1)

For the cruise control to work, connect the CC wire to either Pin 2 of the 3 pin X10170 connector coming out of the FGR module under your dashboard, or wire it directly to Pin 27 X60004 of your MS42/MS43 ECU. This wire should also work for other similar era DBW ECUs including MSS54, MSS52 on the same Pin 27 X60004

You also need to disconnect the FGR module 3 pin plug X10170 if you have an FGR module. Cruise control will not work unless you do this. If it isn't working, also check the brake light bulbs and verify they aren't loose or using a damaged socket/housing.

You can now remove the Cruise Control lever switch along with the wiring and FGR module to gain additional leg room. There are lower column housings that don't have the switch cut out if you want to have a polished look.

There is no software programming/coding etc... required for this to work. However you can check connectivity and button operation using INPA to verify that the buttons are working by going to the corresponding FGR menu in your ECU selection.

So I've used this for a while and everything works flawlessly. Using the ASWC-1 I was also able to double assign functions to the radio I use (Pioneer DEH-80PRS) for short and long press on the buttons.

Remember to pre-center the clockspring prior to installation on your vehicle, Spin it all the way to one side, and then spin it all the way to the other side, counting the turns. Divide by two and rotate it back by that amount. I counted 2.5 turns from any side to center.

Please let me know if you have any questions. Pictures will be added shortly.

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Demonstration Video and Discussion of Operation:
https://www.youtube.com/watch?v=rdyZ9UaLIYY

[Muzz258]

Wow, well done.

I had looked at this mod a couple of times and found it just too hard, not enough wires in the slip ring etc. You've nailed it. Thank you for the write up.

[solimans]

Pic or it didn’t happen


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[TommyMaddox]

Pic or it didn’t happen


Sent from my iPhone using Tapatalk

Pictures and a demonstration video have been added

[BimmerBreaker]

I need to do this at some point. Nice job

[spazzyone]

great job! I was looking for a wheel like that to replace the stock m roadster wheel but all of the ones I saw for sale were single stage. Where did yours?

[TommyMaddox]

great job! I was looking for a wheel like that to replace the stock m roadster wheel but all of the ones I saw for sale were single stage. Where did yours?

This is a single stage wheel. Just use your dual stage airbag and of course the custom slipring. No apparent difference between single and dual stage as far as the actual wheel goes.

[solimans]

Fantastic


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[fmcfad01]

Very cool, i swapped in my e39 M5 steering wheel and have the buttons in a box. Was always curious if you could get them to work. Do these only work with the factory stereo? Assume they do not work with the trafficPro?

[TommyMaddox]

Very cool, i swapped in my e39 M5 steering wheel and have the buttons in a box. Was always curious if you could get them to work. Do these only work with the factory stereo? Assume they do not work with the trafficPro?

I didn't test this with the factory stereo (I used the ASWC-1 Module with a Pioneer DEH80-PRS head unit). I don't see any reason why this wouldn't work on either the factory stereo or the Becker unit as long as both have ibus input and can be used with SWC on other similar era BMWs.

[Davidz3coupe]

Hi Tommy, I want to try this mod, hopefully you will give me a hand if I encounter some trouble. I have all necessary parts. my motor is M54. First question, what is this software you are using on the laptop and how you connect to the can bus?

[TommyMaddox]

Hi Tommy, I want to try this mod, hopefully you will give me a hand if I encounter some trouble. I have all necessary parts. my motor is M54. First question, what is this software you are using on the laptop and how you connect to the can bus?

INPA, have an old panasonic toughbook running a VM. Using an ebay USB to OBDII to round 20 pin connector to interface with the vehicle systems.

[Dan112]

Sorry to resurect an old thread, but I am curious if the steeringwheel without the "speaker man" on the left side would work.