I found instructions on:
There are several strings that address wireless F.O.B. programming. One
tells how to program 1992-1998 AND 1999-2003 Tahoes, but I couldn't find it.
This one was in the Blazer forum but seems to work on my 1997 Tahoe.
1) Ground terminal No. 8[black/white wire (uppermost-rightmost pin when
looking at the data plug)] of Data Link Connector (DLC) Located under lower
left side of dash. Reciever will respond by locking and unlocking doors
within 2 seconds. Press any button of first transmitter to be programmed.
Control module will respond by locking/unlocking all doors and activationg
2) Press any button of second transmitter to be programmed. Control module
will again respond by locking/unlocking all doors and activating hatch
release. Remove ground from DLC terminal 8. Transmitter operation can then
be verified. Attempt all functions with remote."
1997 Tahoe LT 5.7L 4x4