GMC 2004 Savana Van Owner's Manual page 98

To close the sliding side door from outside, use the
outside door handle to slide the door toward the front of
the vehicle.
When the door slides closed completely, it will be flush
with the side of the body.
2-12
To open the sliding door from inside, turn the handle
upward and toward the rear of the vehicle. Then, slide
the door toward the rear of the vehicle to open it.