GMC 1997 Savana Van Owner's Manual page 72

To open the "40" (rear) portion of a 60/40 door from the
outside, pull the handle on the side of the rear door and
pull it toward you.
To close the side doors, close the "40" (rear) door first.
Then close
the
"60" (front) door. Check to make sure
both doors are completely closed.
The front side swing-out door has a check strap assembly
in the door frame to keep the door from opening beyond
90 degrees.
To open the door beyond 90 degrees, close the door
partially, pull the check strap outward at the spring hole
and then open the door. When you close the door, the
check strap will automatically re-engage.
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