Audi A4 electrical problem

Okay, I'm also having a problem with an Audi A4, manufactured in August 2001, with the AWX engine. In this car, the turn signals, high beams, and power windows are no longer working. It's very suspicious that when you turn off the ignition, the radio should normally turn off. However, in this case, it remains on (possibly a faulty ignition switch?). The error indicates a communication failure with the steering column electronics.
I now need to find the wiring diagram and check the circuit for the window lifters and the light switch.

Is the steering column electronics still accessible via diagnostics?