I have looked at the owner manuals but can't find any info about why the radio (Visteon) doesn't have any volume.
Found it!!! Above drivers head in compartment, has 2 position switch, Radio or Home Theater.
I just purchased a 2007 Rev LE, had the same problem, then found it. Mine has a couple issues, wind noise near the passengers side dash when driving over 40 mph, and I can't find where the drinking water filter is. Have a great day.