GMC 2007 Yukon XL Owner's Manual page 182

Vent: To vent the sunroof, press the rear of the
passenger's side switch. To stop the sunroof
partway, press the switch a second time. To close
the sunroof, press and hold the front of the
passenger's side switch. To stop the sunroof
partway, release the switch.
182
Anti-Pinch Feature: If an object is in the path of
the sunroof while 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 open halfway, and the air
deflector will raise. To close the sunroof once
it has re-opened, refer to the "Express-Close" or
"Manual-Close" functions described previously.
If the sunroof is in the vent position, and there is
an object in the path of the sunroof when it
closing, the anti-pinch feature will detect the object
and stop the sunroof. To close the sunroof once
it has re-opened, refer to the "Manual-Close"
or "Express-Close" functions described previously.