GMC 2010 Yukon/Yukon XL Owner's Manual page 362

The AM-FM antenna is located in the passenger rear
side windows. Make sure the inside surfaces of the rear
side windows are not scratched and that the lines on
the glass are not damaged. If the inside surfaces are
damaged, they could interfere with radio reception.
If a cellular telephone antenna needs to be attached to
the glass, make sure that the grid lines for the AM-FM
antenna are not damaged. There is enough space
between the grid lines to attach a cellular telephone
antenna without interfering with radio reception.
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The XM Satellite Radio antenna is located on the roof of
the vehicle. Keep the antenna clear of obstructions for
clear radio reception.
If the vehicle has a sunroof, the performance of the XM
system may be affected if the sunroof is open.