2003 gmc sierra keyless remote programming

Hi, I need help I lot one of my key fobs & purchased one for 2003 gmc sierra. The numbers on back are different. It looks identical. I need to know how to program it. Thanks much,
Janet

Look in the silverado forum, do a search I have seen instructions there on how to program remotes. Its all GM soi it should work fine for your truck.
-Jimmy

First off...if the FCC ID # is the same, it should program. If it is NOT the same, you have the wrong remote. Here is the procedure...

2003 GMC Truck GMC C Sierra - 2WD

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Transmitter Programming

Important
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.


There are 3 methods for programming transmitters, which are listed below as methods 1-3. Up to 4 transmitters may be programmed to the passenger door module (PDM). Each programmed transmitter is given a position of #1-#4 in the PDM memory.

Method 1 - No Tools Required, Program All Transmitters

Important
All transmitters which are to be recognized by the PDM must be programmed in a single programming sequence. When using this program method, all previously programmed transmitters will be erased upon the receipt of the programming signal from the first transmitter.

The order in which the transmitters are programmed will determine its numbering position within the PDM memory. The first transmitter programmed will be transmitter #1, and the second transmitter programmed will be transmitter #2. The number stamped on the transmitter case is for reference only; #2 can be programmed as #1, or vice versa. Additional unnumbered transmitters are also available.


Close all the vehicle doors.
Insert the ignition key into the ignition lock cylinder.
Press and hold the door unlock switch.
While holding the door lock switch in the unlock position, cycle the ignition ON, OFF, ON, OFF.
Release the door unlock switch. The doors will lock and unlock to confirm the program mode.
Press and hold the LOCK button and the UNLOCK button simultaneously on one transmitter. After a delay of approximately 15 seconds, the doors will lock and unlock to confirm the programming of that transmitter.
Repeat the previous step to program up to 4 transmitters.
Turn the ignition switch to the RUN position in order to exit the keyless entry transmitter programming mode.
Operate the transmitter functions in order to verify correct system operation.