BINGO.
You get one or the other, not both.
TECHII configures the radio for a CTS or V.
CTS has the steering wheel volume control, V does not but different functions which need to be sent to other modules (ah so!) while volume control does not.
You still need the base radio to verify some functions that are fault and drive function related (switch closure).
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Also, there was no "Non Nav base unit " (that I know of) for the V. It may have been an option in a base CTS, but a necessity in the V for obvious reasons.
OT, Now you know why GM deserved to go BK.
I have a base CTS non-NAV Radio/CD coming in (they are cheap), and my dealer is friendly. We'll see how the TECHII reprogram goes, and what works and what doesn't. You don't need a "switch closure" to turn off the T/C, I verifed that tearing up some grass last night, but I'll need some open space to verify that you CANNOT turn on competition or totally disable stability control without the OK prompt response.
The lady says that awful nav simply has to go; I did some bezel modifications to put a 7" touchscreen (Pioneer AVIC Z-130) in
Me Precious (2003 anniversary C5 Corvette targa)
and that's the way I want to go here. The buttons are SO ugly, programming is such a PITA, no bluetooth, etc. ad nauseam. Base Radio for DIC with a double DIN unit in place of the CD changer is the goal.
(Pic is a woodgrain base V with such a mod, have straight black one coming in).