GMC 2007 Yukon XL Owner's Manual page 171

Be sure that people and objects are clear of
the garage door or gate operator you are
programming. When programming a garage door,
it is advised to park outside of the garage.
It is recommended that a new battery be installed
in your hand-held transmitter for quicker and
more accurate transmission of the radio-frequency
signal.
Programming Universal Home Remote
Follow these steps to program up to three
channels:
1. Press and hold down the two outside
Universal Home Remote buttons, releasing
only when the Universal Home Remote
indicator light begins to flash, after
20 seconds. Do not hold down the buttons
for longer than 30 seconds and do not repeat
this step to program a second and/or third
hand-held transmitter to the remaining
two Universal Home Remote buttons.
2. Position the end of your hand-held transmitter
about 1 to 3 inches (3 to 8 cm) away from the
Universal Home Remote buttons while
keeping the indicator light in view.
3. Simultaneously press and hold both the
desired Universal Home Remote button
and the hand-held transmitter button. Do not
release the buttons until Step 4 has been
completed.
Some entry gates and garage door openers
may require you to substitute Step 3 with
the procedure noted in "Gate Operator and
Canadian Programming" later in this section.
4. The indicator light will flash slowly at first and
then rapidly after Universal Home Remote
successfully receives the frequency signal
from the hand-held transmitter. Release both
buttons.
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