The steering wheel controls of my R50 Cooper sports type steering wheel stopped working partly. The left side radio controls won't work including the R/T and phone button. The cruise control on the right side is working fine. Oddly the illumination stays on all the time, even if the ignition off, lights turned off and the key is pulled. I tried to check for faliure codes with INPA, but the steeering wheel control is not found/connected. I exchanged the slip wheel, then the right (cruise control) module. The left (radio control) module is a simple resistor ladder, i meassured that and it seem to be ok. I have no clue what else i could do. Any suggestions?

 

sounds like wiring somewhere is kinked or rubbing and shorting.

where, i have no idea but can only guess in the column or at the base where the harnesses pass through

 

The right side button cluster takes the role of the steering wheel module, but it doesn't necessarily have diagnostic connectivity to INPA. To be honest, I don't if it does. Not all satellite modules have this capability.

But, it is supposed to communicate with the GM module over the CAN bus. If the GM module has an error codes or service functions related to the steering wheel, then it might help you find the problem.

 

Before the issues started, the steering wheel controls were diagnosable with inpa. You can check if buttons are pressed an so on. I looked into the wiring diagram. It seems like all connected K-BUS systems are comming together in a connector under the left door entry cover. From there it goes into the GM-Module and from there to the Instrument Cluster. Via K-Bus connected are: Airbag controller, Radio, Dension (CD-Changer), Rainsensor, Immobilizer, Steering Wheel Controlls and Bluetooth. I can control the Dension MP3 player with the radio controlls no problem, Rainsensor seems to work, no airbag warning so i think its working too. Maybe ill try to reprogramm the GM-Module or replace it. Had it replaced with a used one this summer after the old one got blown while installing a trailer hitch.

 

It sounds like you have might have an issue with the +12V/ground to the steering wheel module or a communication fault on the CAN. Make sure you have a clean power source going to/from the module and scan every module in the car to look for faults related to CAN communication issues or internal module faults. Also, try unplugging the dension unit and trailer wiring from the system and see of the problem corrects itself. Slight disruptions to the K-Bus from shoddy wiring or bad modules can cause weird stuff like this to happen.

 

Remove any non-BMW equipment from the vehicle. If you had a short on the ibus you'd know about it. You'd lose the HK audio, the dash lights and winkers would freak out.

I've not inspected R50 but on E46 the steering wheel buttons used one Linbus (iBus) transceiver to send the messages for the distributed volume and phone buttons and to provide the button illumination, and the cruise control messages were sent on an entirely different pin on the slipring for safety.


If there is power the buttons will light at 100% at all times, so check at night. The iBus messages about the dash dimmer setting dims them.

Yes the buttons should be diagnosable with INPA. the iBus is red/white/yellow. Check it for damage under the airbag.