I performed several searches, but could not find my answer. Hope someone can help.

Just bought a 2004 Suburban LS. Has remote keyless entry and came with 1 remote that works. I ordered 2 more from an internet remote site. It came with the following instructions.
1) Close all doors, insert key into ignition, but don't turn it.
2) Hold the unlock button on the drivers side door. Do not release until instructed to do so in Step 4.
3) Quickly turn ignition from ON to Off twice. (On, Off, On, Off) Do not start the car.
4) Release the unlock button. The locks will cycle from lock to unlock signaling that the vehicle has entered Programming mode.
5) Press and hold the Lock and Unlock button at the same time on the first remote. Hold the buttons down until the vehicle responds by locking and unlocking the doors. Repeat this step for additional remotes.
6) Turn the key to the On position to exit the programming mode.

This doesn't work for me. Remotes are not programming. There is a footnote on Step #4 that states if the locks cycle before you release the unlock button the programming will not work because you are not in the programming mode. It suggests that you repeat steps 1-4, and if this doesn't work you probably have a problem with the vehicles keyless entry system.

These are pretty common instructions for seveal GM vehicles so I hope that someone else has encountered this.