GMC 1997 Safari Owner's Manual page 128

Your vehicle's engine should be turned off while
programming the transmitter. Follow these steps to
program up to three channels:
2.
3.
4.
If you have previously programmed a universal
channel, proceed to Step 2. Otherwise, hold down
the two outside buttons on the universal transmitter
until the red light begins
to
flash rapidly
(approximately 20 seconds). Then release the
buttons. This procedure initializes the memory and
erases any previous settings for all three channels.
Hold the end of the hand-held transmitter against the
bottom surface of the universal transmitter so that
you can still see the red light.
Decide which one of the three channels you want to
program. Using both hands, press the hand-held
transmitter button and the desired button on the
universal transmitter. Continue to hold both buttons
through Step 4.
Hold down both buttons until you see the red light
on the universal transmitter flash rapidly. The rapid
flashing, which could take up to 90 seconds,
indicates that the universal transmitter has been
programmed. Release both buttons once the light
starts to flash rapidly.
If you have trouble programming the universal
transmitter, make sure that you have followed the
directions exactly as described and that the battery in
the hand-held transmitter is not dead. If
you still
cannot program it, rotate the hand-held transmitter
end over end and try again. The universal transmitter
may not work with older garage door openers that do
not meet current Federal Consumer Safety Standards.
If you cannot program the transmitter after repeated
attempts, consult your GM dealer.
Be sure to keep the original hand-held transmitter
in case you need to erase and reprogram the
universal transmitter.
Operating the Transmitter
Press and hold the appropriate button on the universal
transmitter. The red light comes on while the signal is
being transmitted.
Note that the effective transmission range of the
universal transmitter may differ from the hand-held
transmitter and from one channel to another.
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