Bose whine/CD

[David Head]

In my new to me V8, I have no right channel, front or rear. I also get a
whine, almost like a capacitor charging up from the other channel at
turn on - it quiets down but can still be heard. I pulled a rear speaker
from my 'down' v8 and connected it - still nothing. I also swapped head
units (its great having 2 V8s!) with no change. Has anyone troubleshot
this kind of wiring problem? The manual doesn't show any other
connectors.
This car also came with a pioneer fm modulated (non functioning) CD of
very ancient lineage - the 6 changer looks like a shoe box. I'm not sure
if this is an oem or add on - it doesn't say Audi anywhere.