1996 Chevrolet Suburban Owner's Manual - Page 74

There are several ways to lock and unlock your vehicle: From the outside: Use your key. From the inside: To lock the door, slide the lever on your door down. To unlock the door, slide the lever up. Power Door Locks (Option) Press the side of the power door lock switch, marked LOCK, on either front door to lock all the doors at once. Press the ribbed side of the switch to unlock all the doors at once. On four-door models, the switch on each rear door works only that door's lock. It won't lock (or unlock) all of the doors - that's a safety feature. 2-7