GMC 2004 Sierra - Manual (Page 295)

Care of Your CD and DVD Player
The use of CD lens cleaner discs is not advised, due to
the risk of contaminating the lens of the CD optics
with lubricants internal to the CD mechanism.
Cleaning the Video Screen
Pour some isopropyl or rubbing alcohol on a clean cloth
and gently wipe the video screen. Do not spray
directly onto the screen and do not press too hard or
too long on the video screen.
Fixed Mast Antenna
The fixed mast antenna can withstand most car washes
without being damaged. If the mast should ever
become slightly bent, you can straighten it out by hand.
If the mast is badly bent, as it might be by vandals,
you should replace it.
Check occasionally to be sure the mast is still tightened
to the cowl. If tightening is required, tighten by hand,
then with a wrench one quarter turn.
XM™ Satellite Radio Antenna
System (48 Contiguous US States)
Your XM™ Satellite Radio antenna is located on the roof
of your vehicle. Keep this antenna clear of snow and
ice build up for clear radio reception.
Chime Level Adjustment
The radio is the vehicle chime producer. To change the
volume level, press and hold pushbutton 6 with the
ignition on and the radio power off. The chime volume
level will change from the normal level to loud, and LOUD
will appear on the display. To change back to the default
or normal setting, press and hold pushbutton 6 again.
The chime level will change from the loud level to normal,
and NORMAL will appear on the display. Each time the
chime volume is changed, three chimes will sound as an
example of the new volume selected. Removing the radio
and not replacing it with a factory radio or chime module
will disable vehicle chimes.
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