Cadillac CTS 2008 Owner's Manual page 142

Vent Feature: Press and hold the front of the switch
to vent the sunroof. Press and hold the rear of the switch
to close the vent.
Sunroof Feature: Press the rear of the switch to open
the sunroof, and the front of the switch to close it.
2-64
The passenger side switch
operates the sunroof.
Anti-Pinch Feature
If an object is in the path of the sunroof when it is
closing, the anti-pinch feature will detect the object
and stop the sunroof from closing at the point of
the obstruction. The sunroof will then return to the
full-open or vent position. To close the sunroof once
it has re-opened press and hold the front of the
passenger's side switch.