[KMani1]

In the morning when first start the car the horn came on. So I disconnect the horn wire at the horn. During driving I notice that my NAV did not show the map when I press map, and the CD still work fine but the steering volume control not working have to adjust from the nob at the Command.
Coming back from work try reconnect the horn to see the problem still excist and it did. I notice I unplug the ground (Brown wire) this time I disconnect the power and leave the ground on, I got the NAV or MAP back on but the volume control from the steering still not working.
My primary suspect was the clockspring. What else connect to the same circuit of clockspring beside the horn.
Any advices/info greatly appreciated.:surrender::bowdown:

 

[rudeney]

The clockspring sounds like the culprit, but it could also be a faulty steering wheel controller. I'd get codes pulled before tearing into it.

 

[KMani1]

Thanks Rodney.
Should the code be pulled by OBD or SDS? Any diagram or pictures location of the controller and part # greatly apprecoated.

 

[schumicat]

i doubt OBD scan would help.

 

[rudeney]

Unless you have a specialized, high-end OBDII tool that can read MBZ-specific systems, you'll need SDS.