Oldsmobile Alero 3,4L built in 2000 Radio

Hello dear Alero fans! I already had a question about the rear boxes of the Alero. In the meantime I saw that there is a fuse in the fuse box for an amplifier? If this is not on the radio you can hopefully tell me where it was installed? At the front everything is normal but at the back nothing arrives. The fuse is OK. If I connect 8 Ohm Sattelitenboxen back to the cable comes a little bit from the music but apparently this amplifier is probably defective. B The radio is a block with CD, radio and cassette part of Delco. I hope you can help me?!? Thank you for your efforts!!! MfG Norbert