radio cd player amp is there a relay on 2000 BMW 323Ci

radio works then it does not. Checked fuses in stero and fuse box . Soped working and I do not know why. This car has 6 cd changer and nav.
Is there a relay for this stero or amp? Is the computer keepin it from working because I am changing speakers.

Asked by for the 2000 BMW 323Ci