Pontiac 2006 G6 Owner's Manual page 128

4. The hardtop switch is located on the headliner .
To lower the hardtop, press and hold the switch
rearward until the cycle is complete.
2-46
The windows and trunk lid will open. The hardtop will
automatically lower, and the trunk lid will close and latch.
If the engine is on, a chime will sound when the hardtop
has lowered completely. The Driver Information Center
(DIC) will display TOP MOVE COMPLT. See DIC
Warnings and Messages on page 3-46 for more
information.
After the hardtop has lowered completely, release the
switch. If you continue to press the switch for about
two seconds after the hardtop has completely lowered,
the windows will automatically close.