1999 Tahoe keyless entry remote programing

I have bought a keyless remote from ebay that did not come with programing instructions, For my 1999 Chevy Tahoe...this is a extra remote... I have the original one that works great and bought the exact remote that i have
GM P/N 12490830 for a back up.

I took it to local gm dealer and they didnt seen to know what they were doing and just said it dosnt work
(becuse the 2 argued with themselves on how to do it)
so I would like to try myself dose anyone know where to find instructions on how to do this???? or have any sugestions on what to do? thanks for any help Dan

Base models
If they key is in the ON position during the programming procedure, the horn chirp will be disabled, if the key is in the OFF position, the horn chirp will be enabled. The horn will chirp when the lock button is pressed two times.
When reprogramming the remote control door lock reciever, All transmitters must be programmed at this time in order for the transmitters to operate the vehicle. Transmitters not programed at this time will not work and the procedure will have to be redone with all the transmitters.
1. Ground pin 4 to pin 8 of the data link connector (DLC). The receiver will respond by locking and unlocking the doors, and activating the liftgate window release (if equipped) within 2 seconds.
2. Press and hold the LOCK and UNLOCK buttons simultaneously on the first transmitter to be programmed until the locks cycle (approximately 10 seconds).
3. Repeat step 2 for up to four total transmitters to be programmed (if available). The receiver will respond by locking and unlocking the doors and activating the liftgate window release (if equipped) within 2 seconds.
4. Remove the ground applied to the DLC.
5. Lock and unlock the doors in order to verify the transmitter operation.
6. Activate the rear window release in order to verify the transmitter operation.
Luxury models
If they key is in the ON position during the programming procedure, the horn chirp will be disabled, if the key is in the OFF position, the horn chirp will be enabled. The horn will chirp when the lock button is pressed two times.
When reprogramming the remote control door lock reciever, All transmitters must be programmed at this time in order for the transmitters to operate the vehicle. Transmitters not programed at this time will not work and the procedure will have to be redone with all the transmitters.
1. Ground pin 4 to pin 8 of the data link connector (DLC). The receiver will respond by locking and unlocking the doors, and activating the liftgate window release (if equipped) within 2 seconds.
2. Press and hold the LOCK and UNLOCK buttons simultaneously on the first transmitter to be programmed until the locks cycle (approximately 10 seconds).
3. Repeat step 2 for up to four total transmitters to be programmed (if available). The receiver will respond by locking and unlocking the doors and activating the liftgate window release (if equipped) within 2 seconds.
4. Remove the ground applied to the DLC.
5. Lock and unlock the doors in order to verify the transmitter operation.
6. Activate the rear window release in order to verify the transmitter operation.

I will give it a try Thanks so much for the quick response BVR

I tried the method of programming s key fob I purchased on Ebay. GM model #12495653. I have a 1999 Tahoe LT. The locks went on and off after placing the jumper but while holding the Lock and Unlock button, nothing.