GMC 2007 Yukon XL Owner's Manual page 318

(Power/Volume): Turn this knob clockwise or
O
counterclockwise to increase or decrease the
volume of the portable player. You may need to do
additional volume adjustments from the portable
device if the volume does not go loud or soft
enough.
BAND: Press this button to listen to the radio
when a portable audio device is playing. The
portable audio device will continue playing, so you
may want to stop it or power it off.
DVD/CD AUX (CD/Auxiliary): Press this button to
cycle through DVD, CD, or Auxiliary when
listening to the radio. The DVD/CD text label and
a message showing track or chapter number
will appear on display when a disc is in either slot.
Press this button again and the system will
automatically search for an auxiliary input device,
such as a portable audio player.
318
If a portable audio player is not connected, "no
aux input device" will be displayed. If a disc is in
both the DVD slot and the CD slot the DVD/CD
AUX button will cycle between the two sources and
not indicate "no aux input device". If a front
auxiliary device is connected, the DVD/CD AUX
button will cycle through all available options, such
as: DVD slot, CD slot, Front AUX, and Rear
AUX (if available). See "Using the Auxiliary Input
Jack(s)" later in this section, or Rear Seat
Entertainment System on page 321, "Audio/Video
(A/V) Jacks" for more information.