GMC 1993 Safari Owner's Manual page 69

PO438
To unlock the front doors and the sliding side door from the inside: Slide the
lock levers up.
To unlock the rear hatch and split-panel doors from the inside: Push the top
of the switch.
Power Door Locks
PO439
If your vehicle has power door locks, push the power door lock switch to lock
or unlock all the doors at once.
2-1 1