199002625 - N070 CONTROLS ON THE STEERING WHEEL NOT WORKING

When the buttons on the front panel of the radio are pressed the corresponding functions are selected. Whilst when the controls on the steering wheel are operated the corresponding function is not selected.
Test results
1OPERATION CHECKAll OKProblems encounteredOperation
Using the controls on the steering wheel, check the correct operation, even in steering conditionsMove on to Step 21. One of the controls on the steering wheel faulty2. All the controls on the steering wheel faulty1. Move on to Step 22. Move on to Step 3
2STEERING WHEEL MODULE CHECKAll OKProblems encounteredOperation
Check the following, in order:- Correct power supply for the module on the steering wheel- Continuity of the wiring- Operation of controls on the steering wheel    See E3510 RADIO Move on to Step 31. Wiring faulty2. Controls on the steering wheel faulty1. Restore the wiring to correct operation2. Repair / replace the controls on the steering wheel
3RADIO MODULE CHECKAll OKProblems encounteredOperation
Check that the reception of the signals from the module on the steering wheel is correct at the radio connector    See E3510 RADIO End of diagnosisControls from radio steering wheel conversion module faultyReplace the radio    Op. 5570T80 CAR RADIO EQUIPMENT - R+R