1976 Dart - ignition switch

You would expect the radio to be connected to the ACC circuit but it's not which begs the question, what is connected to the ACC circuit? I reviewed the 1976 book and the 1975 diagram at mympar. They are apparently identical as far as the radio circuit is involved. I checked the wire indicated with a voltmeter. It was not hot in the ACC position. Could it be that there actually is no ACC wire?