GMC Yukon 2007 Owner's Manual page 186

2. Locate in the garage, the garage door opener
receiver (motor-head unit). Locate the "Learn"
or "Smart" button. It can usually be found
where the hanging antenna wire is attached
to the motor-head unit and may be a
colored button. Press this button. After you
press this button, you will have 30 seconds to
complete the following steps.
186
3. Immediately return to your vehicle. Press and
hold the universal home remote button that
you would like to use to control the garage
door until the garage door moves. The
indicator light, above the selected button,
should slowly blink. You may need to hold the
button from five to 20 seconds.
4. Immediately, within one second, release the
button when the garage door moves. The
indicator light will blink rapidly until
programming is complete.
5. Press and release the same button again.
The garage door should move, confirming
that programming is successful and complete.
To program another Rolling Code device such
as an additional garage door opener, a security
device, or home automation device, repeat
Steps 1-5, choosing a different function button in
Step 3 than what you used for the garage door
opener.
If these instructions do not work, you probably
have a Fixed Code garage door opener. Follow the
Programming instructions below for a Fixed
Code garage door opener.