2008 Chevrolet Trailblazer Remote Programming Procedure:
WARNING: Before entering remote learning mode, have in possession all transmitter you want to use on the car, including old ones you want to keep working. The moment you program the remote, all previous learned fobs will be deleted from the memory. The other transmitters will not be functional until you program the keyfobs again.
1. Close all car doors, windows closed, wait for dome light to turn off.
2. Put key in ignition.
3. Hold down the power UNLOCK button on the driver’s door panel-do not release until step 9.
4. Perform steps 5-8 quickly.
5. Switch the ignition switch to the ON position (as far as you can go WITHOUT starting the engine).
6. Move the ignition switch to the OFF position.
7. Turn the ignition switch to the ON position.
8. Move the ignition switch to the OFF position.
9. Let go of the power unlock button on the door panel. The car will lock and unlock the doors to confirm.
10. Hold down the LOCK and UNLOCK buttons on the transmitter in unison until the door locks cycle. This step may take up to 30 seconds.
11. Repeat step 10 for each and every additional keyfob(including any existing fobs).
12. Switch the ignition switch to the ON position in order to exit the keyfob learning method.