Chevrolet 2000 Express Van Owner's Manual page 80

There are several ways to lock and unlock your vehicle.
If your vehicle is equipped with remote keyless entry,
see "Keyless Entry System" later in the Index for
more information.
From the outside, use your key.
2-4
To lock the door from the
inside, slide the lever on
your door down.
To unlock the door, slide the
lever up.
Power Door Locks (Option)
When a door is locked, the inside door handle will
not work.
Press the bottom side of the
power door lock switch to
lock the doors at once.
yellowblue