Both keyless remote not will not easily unlock the doors.

Remote Transmitter Programming NOTE: All keyless entry remote transmitters must be programmed at the same time.
NOTE: Programming (or reprogramming) the keyless entry remote transmitters into the central security module can be accomplished using a diagnostic tool or by carrying out the following steps.

1. Turn the ignition switch from OFF to RUN eight times within 10 seconds, ending in RUN. If the module has successfully entered program mode, it will lock and then unlock all doors.

1. Within 20 seconds, press any button on a keyless entry remote transmitter, and the doors will lock and then unlock to confirm that each keyless entry remote transmitter has been programmed. Repeat this step for each transmitter.

1. If the door locks do not respond for any keyless entry remote transmitter, wait several seconds and press the button again. If the door locks still fail to respond, refer to Inspection and Verification.

1. Turn the ignition switch to the OFF position, or wait up to 20 seconds after Step 2, to exit program mode. If a keyless entry remote transmitter has been programmed (or reprogrammed), the doors will lock and unlock one last time to confirm.

The keyless entry system is controlled by the (GEM) - generic electronic module .
Keyless Entry The electronic door lock system has two main components:

• generic electronic module (GEM)(14B204)
• keyless entry remote transmitter (15K601)
• NOTE: Battery power and ground must be remove before disconnecting the GEM connectors to avoid setting false codes.
  Power Locks Operation The power locks feature allows the customer to lock and unlock the doors via momentary switches located on the driver and passenger door. When the GEM detects a momentary press of the driver or passenger lock button, the GEM will supply power to the driver or passenger lock actuators for approximately 250 ms from relays internal to the GEM. When the GEM detects a momentary press of the driver or passenger unlock button, the GEM will supply power to the driver or passenger unlock actuators for approximately 250 ms from relays internal to the GEM.
  Remote Keyless Entry Door Locks Operation The remote entry feature allows the customer to unlock the driver door, unlock all doors, and lock all doors using a valid remote transmitter as long as the ignition switch is not in RUN or START. The driver door is unlocked whenever the GEM detects a valid remote transmitter unlock transmission. All the doors are unlocked when the GEM detects a second valid remote transmitter unlock transmission within three seconds of the first transmission. All the doors are locked when the GEM detects a valid remote transmitter lock transmission. If the GEM detects a second valid remote transmitter lock transmission within three seconds of the first transmission, the doors will lock again, the horn will sound for 20 ms and the parking lamps will flash for 200 ms to indicate the doors are locked. If the GEM detects the driver or passenger door is ajar during the second lock transmission, the doors are locked again and the horn is sounded twice. If the GEM detects a valid remote transmitter lock transmission within three seconds of detecting a valid remote transmitter unlock transmission, the GEM will lock all the doors
• • The doors do not lock/unlock using the remote transmitter
  • Ignition switch.
  • GEM.
  • Remote transmitter.
  • Remote transmitter batteries.
  • GO to Pinpoint Test C .
  You followed the program instructions to the letter ? Programming -Keyless Entry Remote Transmitter NOTE: All keyless entry remote transmitters (15K601) must be programmed at the same time.
  NOTE: All previous transmitter identification codes (TIC's) will be erased when programming mode is entered.
  NOTE: To program (or reprogram) the keyless entry remote transmitters into the generic electronic module (GEM)(14B204), perform the following steps.
  
  1. Turn the ignition from OFF to RUN eight times within 10 seconds, ending in RUN. If the GEM has successfully entered program mode, it will lock and unlock all the doors.
  1. NOTE: The first TIC must be entered within 7.5 seconds of entering the program mode and additional TICs must be entered within 7.5 seconds of the first TIC. The programming mode is exited whenever the timing constraints are not met.
     Press any button on a keyless entry remote transmitter, and the doors will lock and then unlock to confirm that each keyless entry remote transmitter has been programmed.
  1. If the door locks do not respond for any keyless entry remote transmitter, wait for several seconds and press the button again.
  1. Turn the ignition switch to the OFF position, or wait up to five minutes after step 1, to exit program mode. If a keyless entry remote transmitter has been programmed (or reprogrammed), the GEM will lock and unlock all the doors one last time.
  1. Take an have the vehicle checked for DTC'S

B1396 Power Door Lock Circuit Short to Battery GEM GO to Pinpoint Test B . B1397 Power Door Unlock Circuit Short to Battery GEM

Hi.

To program ( or reprogram ) a keyless entry remote transmitter into the remote keyless entry module, perform the following steps:

1. Turn the key to ON or ACC and short the two terminals of the program connector, a two-pin connector located below the driver's side of the instrument panel at the base of the steering column. All doors should lock and then unlock.
2. Press any button on each keyless entry remote transmitter in turn. All doors should lock and then unlock. If the door locks do not respond, press the button again (up to three times maximum with the same keyless entry remote transmitter). If the door locks still fail to respond, go to Pinpoint Test A.
3. Repeat Step 2 to program additional keyless entry remote transmitters into the remote keyless entry module (up to four keyless entry remote transmitters maximum).
4. Turn key off.
5. Remove the short from the program connector. All doors should lock and then unlock.
6. Verify that the keyless entry remote transmitters have been successfully programmed by pressing the LOCK or UNLOCK button on each one, and observing that the system responds by locking and/or unlocking the doors.


I hope this helps you.

Thanks!

Try reprogramming the remotes. Here are the instructions for the procedure. Hope it helps. Cobra!
Programming NOTE: All keyless entry remote transmitters (15K601) must be programmed at the same time.
NOTE: To program (or reprogram) the keyless entry remote transmitters into the RAP module, perform the following steps:

1. Make sure that the anti-theft system is not armed or triggered.

1. Turn the ignition switch (11572) from OFF to RUN eight times within ten seconds, ending in RUN. If the RAP module has successfully entered program mode, it will lock and then unlock all doors.

1. Within 20 seconds, press any button on a keyless entry remote transmitter, and the doors will lock and then unlock to confirm that each keyless entry remote transmitter has been programmed. Repeat this step for each transmitter.

1. If the door locks do not respond for any keyless entry remote transmitter, wait several seconds and press the button again. If the door locks still fail to respond, refer to Inspection and Verification.

1. Turn the ignition switch to the OFF position, or wait up to 20 seconds after step 2, to exit program mode. If a keyless entry remote transmitter has been programmed (or reprogrammed), the RAP module will lock and unlock all doors one last time to confirm.

Programming Electronic Door Lock Control System NOTE: The electronic door lock control processor (14B001) erases all previous keyless entry remote transmitter (15K601) from memory when the keyless entry remote transmitters are programmed or reprogrammed. The electronic door lock control processor can store up to four keyless entry remote transmitters in memory.

• To program (or reprogram) keyless entry remote transmitter into the electronic door lock control processor, perform the following steps:

1. Turn ignition switch to the RUN position and momentarily short the two terminals of the program connector taped to the wire assembly and located behind the glove compartment. All doors should lock and then unlock. Remove shorting pin.
   

1. Press any button on keyless entry remote transmitter. All doors should lock and then unlock to verify the keyless entry remote transmitter has been programmed. If door locks do not respond, press button again (up to three times maximum with the same keyless entry remote transmitter).
   

1. Repeat the above step to program additional keyless entry remote transmitters into the electronic door lock control processor (up to four keyless entry remote transmitters maximum).
   

1. Turn ignition switch OFF. All doors should lock and then unlock.
   

1. Check operation.
   

Programming
When
Remote control added or replaced. System malfunction.
How
Obtain all remote controls. Remove key from ignition switch. Close all doors. Open driver's door. Carry out the following within 24 seconds: Turn ignition switch ON and back to LOCK position 3 times. Remove key. Press and release driver's door courtesy light switch 3 times. Ensure doors lock and unlock. If not, wait 40 seconds and repeat procedure starting with driver's door already open. Press each remote control lock or unlock button twice. Ensure doors lock and unlock after each remote control operation. If not, proceed as follows: Press and release driver's door courtesy light switch once. Ensure doors lock and unlock twice. Repeat procedure starting with driver's door already open.
NOTE: A maximum of 3 remote controls can be programmed.

. Enter 5-digit permanent entry code into the keyless entry driver door keypad. 2. Within 5 seconds of pressing last button of code, press the 1/2 button. All doors will lock then
unlock confirming you are in programming mode.
3. Press any button on first Keyless Remote within 5 seconds of pressing the 1/2 button. Locks will
cycle to indicate succesful programming.
4. If you are programming more than one Keyless Remote (Including any exsiting remotes) Press
any button on second keyless remote within 5 seconds of previous remote. Locks will cycle again
to indicate succesfull programming. (If the keypad light goes out before all remotes are
programmed the entire process must be repeated).
5. Press the 7/8 and the 9/0 buttons simultaneously on the keypad to exit program mode.

Instructions to program a keyless entry remote for a Chevy Silverado. They also work on 2003, 2004 and 2006 Suburbans.

1. Close all the vehicle doors.
2. Insert the ignition key into the ignition lock cylinder.
3. Press and hold the DOOR unlock switch.
4. While holding the DOOR lock switch in the unlock position, cycle the ignition ON, OFF, ON, OFF.
5. Release the DOOR unlock switch. The doors will lock and unlock to confirm the program mode.
6. Press and hold the LOCK button and the UNLOCK button simultaneously on one keyless remote. After a delay of approximately 15 seconds, the doors will lock and unlock to confirm the programming of that transmitter.
7. Repeat the previous step to program up to four transmitters.
8. Turn the ignition switch to the RUN (one more click forward) position in order to exit the keyless entry transmitter mode.
9. Operate the transmitter functions in order to verify correct system operation

On this model you will have to open glove box and press the tabs on each side so that you can open it all the way open. You will see a 2 wire grey connector behind it.
Turn ignition switch to run postion then take a paper clip or something like that and momentarily short the 2 wires together.
The door locks should then cycle from lock to unlock.Remove the paper clip then press one of the buttons on each remote. When you press the button on the remote door locks should cycle again to confirm that it programed.Then when finished turn off the ignition switch and door locks should unlock to confirm you have exited programming mode.

System operation
System will automatically lock all doors when vehicle is driven in excess of 15 mph
Pressing UNLOCK (on remote) once deactivates system and unlocks driver door only
Pressing UNLOCK (on remote) twice w/in 5 seconds deactivates system and unlocks all doors
Alarm/central locking functions can be altered using remote transmitter


Programming

Access data link connector (DLC)- druvers sude fascia
Switch ignition on
Jump DLC terminal 1 and ground
Ensure doors lock and unlock, indicating programming mode active
Press any button of each remote to be programmed
Ensure doors lock and unlock after each remote operation - indicating programming complete
Remove jump lead to exit programmming code

A maximum of two remotes can be programmed