GM Service Manual Online
For 1990-2009 cars only

To unlock all doors from inside the vehicle, press the front of the power door lock switch on either front door.

If the content theft-deterrent system is armed, the power door lock switch will not unlock the doors until the system is disarmed. See Content Theft-Deterrent for more information on disarming the system.

You can lock all doors from inside the vehicle by pressing the rear of the power lock switch on either front door. The content theft-deterrent system, may be programmed to arm the system when the rear of the power lock switch is pressed. See Content Theft-Deterrent System for more details.