Pontiac 1999 Firebird Owner's Manual page 128

3. Pull down on the center opening and align the hooks
with the holes. Push forward on the larger part of the
latch until it clicks. Do not force the latch. If it is
hard to lock, the top is not properly aligned.
2-72
NOTICE:
The convertible top may be tight when pushing
forward on the latch when your vehicle is new,
but it will loosen up with time. Make sure that
the hooks are properly aligned before using any
kind of force.
If your vehicle has a power loss, such as a dead battery,
you can still raise or lower the top manually by turning
the valve in the driver's side of the hatch.
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