Instructions to program a keyless entry remote for a GM Truck i.e. Chevy Silverado, Avalanche, Tahoe etc.. They also work on 2003, 2004 and 2006 GM models. (NOTE - The GM dealer will charge $35.00 to do this 1 minute task - what a rip!)

[edit] Steps

Close all the vehicle doors.
Insert the ignition key into the ignition lock cylinder - do not turn ignition switch.
Press and hold the DOOR unlock switch (This is the switch on the door, NOT the remote).
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 one time to confirm the program mode is actuvates.
Simultaneously press and hold the LOCK button and the UNLOCK button on one keyless remote for approximately 15 seconds, the doors will lock and unlock to confirm the programming of that transmitter.
Repeat the previous step to program up to four transmitters. Reprogram any existing remotes at this time as they have been erased.
Turn the ignition switch to the ON (one more click forward) position in order to exit the keyless entry transmitter mode.
Operate the transmitter functions in order to verify correct system operation.

[edit] Tips

On a 2006 Suburban, the first keyless entry programmed will set to Driver 1, and the second to Driver 2.
If it doesn't work, verify your vehicle is equipped with a keyless entry system by entering your VIN at http://www.keylessride.com
Works for 2005 TrailBlazer too.