Here is a reply to a similar question:
Here is the answer to your question, but it looks like you will
have to take it to the dealer since the Fobs have to be programmed
with a scan tool.
Transmitter Programming
Transmitter Programming
Important
All transmitters which are to be recognized by the remote control door lock receiver (RCDLR) must be programmed in a single programming sequence. If the system is placed in program mode it will erase all previously programmed transmitters upon the receipt of the programming signal from the first transmitter. Up to 4 transmitters can be programmed. Do not operate or program the transmitters in the vicinity of other vehicles that are in the keyless entry program mode. This prevents the programming of the transmitters to the incorrect vehicle.
Install a scan tool.
Turn ON the ignition, with the engine OFF.
Use the scan tool in order to access the Body Control Module (BCM) Special Function: Program Key Fobs.
Press the START soft key on the scan tool.
Important
The scan tool must stay connected until all of the transmitters are programmed.
Press and hold the LOCK button and the UNLOCK button simultaneously on one transmitter. After a delay of 5-10 seconds, the locks will cycle in order to confirm the programming of that transmitter.
Repeat the previous step in order to program up to 4 transmitters.
Remove the scan tool.
Operate the transmitter functions in order to verify correct system operation.
__________________
John
[email protected]
2003 Silverado LS 4.3
Flowmaster 40 Series dual out -- Hypertech Programmer III -- K&N CAI
Westin 2" lowering shackels -- Escalade dash bezel -- Coachworks Billet Grille
GM Billet Bowtie -- Escalade Inner/Outer chrome door handles