What connects the CLS, stereo sound (the screen works and i can change channels, i just dont get sound), OBC read out, and window motor electronically?

I am getting random black outs while im driving, or when the car is parked and none of those work all of a sudden, but a couple minutes later work again.

Dash lights work, headlights work, and all heating and a/c work while this is happening.

Could it be a bad amp? Where do they all get their power from? HELP!