[Jimbotronics]

Here's the instructions for my 04 Avalanche. Don't know if it's the same for an 06 - worth a try nonetheless ey?

Programmable Automatic Door Locks - Programming Steps

All Chevrolet Avalanche models come equipped with Programmable Automatic Door Locks. From the factory your locks are programmed to lock all doors when you shift out of Park, and to unlock all doors when you shift into Park. They are also programmed out of the factory to lock the doors when you exceed approximately 15 MPH if the doors are unlocked (say if you did that manually). This is both a safety and a convenience feature.

You can reprogram the Automatic Door Locks to operate to your liking, or completely disable them. The locks can be programmed with four possible settings.

To program your locks read these instructions all the way through first and then follow them:

Put the key into the ignition but leave it OFF (don't turn the key). This is very important.

Bull the turn signal/multifunction lever towards you (as if you were turning on your high beams) and hold it. Do not release the lever. This is also very important.

While still holding the turn signal lever towards you turn the key to RUN (not START) and then back to OFF (not ACCESSORY) twice. When you return the key to the OFF position for the second time release the turn signal. The door locks should lock and unlock. If this does not happen you need to repeat steps one through three.

You now have 30 seconds to reprogram the door locks. You have four possible options

ALL DOORS LOCK/DRIVER'S DOOR UNLOCKS
On the driver's door press the Lock Button once and then the Unlock Button once.

ALL DOORS LOCK/ALL DOORS UNLOCK
On the driver's door press the Lock Button once and then the Unlock Button twice.

ALL DOORS LOCK/NO DOORS UNLOCK
On the driver's door press the Lock Button once and then the Unlock Button three times.

NO DOORS LOCK/NO DOORS UNLOCK
On the driver's door press the Lock Button twice.

If you want to cancel reprogramming the door locks during this time simply turn the key to RUN (not START) and the doors will lock and unlock again. This indicates the procedure has been cancelled and the original setting has been retained.

If you take longer than thirty seconds the doors will automatically lock and unlock, also indicating the procedure has been cancelled.

You can reprogram the locks as many times as you like