GMC Yukon Denalid Owner's Manual page 169

Do not use the this system with any garage door
opener that does not have the stop and reverse
feature. This includes any garage door opener
model manufactured before April 1, 1982.
Read the instructions completely before attempting
to program the transmitter. Because of the
steps involved, it may be helpful to have another
person available to assist you in programming
the transmitter.
Be sure to keep the original remote control
transmitter for use in other vehicles, as well as,
for future programming. You only need the
original remote control transmitter for fixed code
programming. It is also recommended that
upon the sale or lease termination of the vehicle,
the programmed buttons should be erased for
security purposes. See "Erasing your Universal
Home Remote Buttons" later in this section.
Be sure that people and objects are clear of
the garage door or security device you are
programming. When programming a garage door,
it is advised to park outside of the garage.
If you do not know if your garage door opener
is a fixed code or rolling code device, open your
garage door opener's remote control battery cover.
Your garage door opener is a fixed code device
if a panel of DIP switches is present. If not,
your garage door opener is a rolling code device.
169