Chevrolet 2005 Blazer Owner's Manual page 79

The tailgate can be opened without a key if the driver's
door is unlocked. The liftglass will not release if the
vehicle is in gear.
To lock a power door lock system from the outside,
insert the key into a lock button and turn clockwise. All
doors, the tailgate and liftglass, or liftgate will lock.
Reach inside the tailgate
to lift the handle and open
the tailgate.
Remote Liftglass Release
If your vehicle has an automatic transmission, your shift
lever must be in PARK (P) or NEUTRAL (N) for the
release to work.
If you have a manual transmission, you must apply your
parking brake or have the ignition off before you can
open the liftglass.
The REAR HATCH button,
located to the right of the
steering wheel on the
instrument panel, allows
you to release the liftglass
from inside the vehicle.
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