2009 Chevrolet Trailblazer Remote Programming Procedure:
IMPORTANT: Before initiating programming mode, have in-hand every transmitter you want to use on the vehicle, including old ones you want to keep working. When you program the remote, all previous learned transmitters will be deleted from the memory. The other fobs will not be functional until you program the keyfobs again.
1. Close all vehicle doors, all windows closed, wait for dome light to turn off.
2. Put key in ignition.
3. Press and Hold the power UNLOCK button on the driver’s door panel-do not release until step 9.
4. Do steps 5 to 8 very fast.
5. Rotate 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. Flip the ignition switch to the ON position.
8. Flip 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 as well until the door locks lock and unlock. This step may take up to Half a minute.
11. Repeat step 10 for each and every additional remote(including any existing transmitters).
12. Turn the ignition switch to the ON position in order to quit the transmitter programming mode.