Bob,
I looked up the part number in EPC. If you don't subscribe, you probably should. Any way in typical German that part is called a "parasitic stopper" and is located inside the left c-pillar. It also shows another with the part number A140 820 36 89 Couldn't see what the difference was though. And have you contacted Becker Radio Service back in New Jersey? They might be able to shed some light on this.
Anziani
'97 CL600 52K