Pontiac 1998 Trans Sport Owner's Manual page 115

Door Locks
Unlocked doors can be dangerous.
Passengers
==
especially children
--
can easily
open the doors and fall out.
When a
door is
locked, the inside handle won't open
it.
Outsiders
can
easily enter through an unlocked
door when you slow down or stop your vehicle.
This may not be so obvious: You increase the
chance of being thrown out of the vehicle in a
crash if the doors aren't locked, Wear safety belts
properly, lock your doors, and you will be far
better off whenever you drive your vehicle.
There are several ways to lock and unlock your vehicle,
From the outside, use your key or the remote keyless
entry transmitter (if your vehicle has this option).
To unlock either front door from the outside with the
key, insert the key and turn it toward the front of
the vehicle.
You can lock either front door from
the
outside with
your key by inserting and turning it toward the rear of
the vehicle.
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