GMC 2011 Yukon XL Denali Owner's Manual page 55

When the sunroof is opened, an air
deflector will automatically raise.
The air deflector will retract when
the sunroof is closed.
The sunroof also has a sunshade
which can be pulled forward to block
sun rays. The sunshade must be
opened and closed manually.
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.
Dirt and debris may collect on the
sunroof seal or in the track. This
could cause an issue with sunroof
operation, noise, or plugging the
Keys, Doors and Windows
water drainage system. Periodically
open the sunroof and remove any
obstacles or loose debris. Wipe the
sunroof seal and roof sealing area
using a clean cloth, mild soap, and
water. Do not remove grease from
the sunroof.
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