After changing the steering rack, there are some problems with some electrical equipment:
the Stability control was on after the rack job, then went off, then suddenly came back on while driving on the highway at about 120 kms/hr, then was off again next morning. Pushing the button while it puts itself on does not disengage it.
The dash says that the third brake light bulb is fried, but it actually seems to be on perfectly fine
Stereo has gone dead. No power to it.

NOTE:
Issues were absolutely non-existent prior to rack job with any of these things.
Stereo was pretty much perfect with the exception of the reception issue that depends on the thing on top of the rear window.

2002 Audi A4 1.8t Quattro
I did not do the job, I had a friend of mine do it for me. I won't see him until next week and that's why I'm trying to figure out what it could be.
He's a certified mechanic and knows what he's doing very very well, I can't see him forgetting to reconnect stuff, as well as I can't see him chopping something off accidentally and not fixing it/realizing it.
Thank you