GMC Sierra Denali Classic 2007 Owner's Manual page 227

Both sets of rear seat headphones may include
foam ear pads that can be replaced.
Foam ear pads on these headphones may
become worn or damaged. The headphone foam
ear pads can become damaged if they are not
handled or stored properly. If the foam ear pads do
become damaged or worn out, the pads can be
replaced separately from the headphone set.
It is not necessary to replace the complete
headphone set.
The headphone replacement foam ear pads can
be ordered in pairs. See your dealer for more
information.
Battery Replacement
To change the batteries, do the following:
1. Loosen the screw on the battery compartment
door located on the left side of the headphone
earpiece.
2. Replace the two AAA batteries in the
compartment. Make sure that they are
installed correctly, using the diagram on the
inside of the battery compartment.
3. Tighten the screw to close the
compartment door.
If the headphones are to be stored for a long
period of time, remove the batteries and keep them
in a cool, dry place.
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