Not sure if this will help, but it may give you a rough idea. Mine is a Becker Grand Prix BE2140 with an Alpine 6CD Changer hooked up. In this link -

http://www.peachparts.com/shopforum/showthread.php?t=240513&page=2&highlight=cassette+stuck

you'll see a pix of the rear of the unit with the wires attached. Unfortunately, I do not have a power antenna. Mine is a fix metal rod which is up all the time. Next pix shows all the wires which are NOT connected and left "hanging' behind the unit. The unit is working fine so those loose wires are I suppose meant to be loose.

Sorry I can't be of more help.