Ok, I'm pretty sure I know what this one is, but before I just go recklessly applying power to unknown wires I figured I'd better ask around. Someone in the past had removed the radio, by cutting all the wires. I figured out all the speaker wires and the switched power and ground, and added in a hot wire for a memory circuit (tapped off of the hot wire pin at the hazard switch connector). I have one wire left which I believe went to the radio before for a power antenna control, it is a blue wire with stripe, individually sheilded in its own black sleeve going into the dash. Am I correct on this assumption? It does not have any power to it right now with key on or off (checked via voltmeter). If this is an antenna wire, what is the purpose of the switch on the dash? (My owners manual is in German so I cant understand the whole of it, as I'm not completely fluent).

1980 240D w/617 motor