The 2005 Chrysler Pacifica came standard with a manual-open rear liftgate that used an electric latch in place of the typical mechanical-style latch. The Pacifica also had a power liftgate option that opened and closed the liftgate at the press of a button.
Unlock the doors, if needed, by pressing the "Unlock" button on the remote keyless entry remote or by pressing the unlocking button in the vehicle. Look under the license plate and find the handle cutout. Reach into the handle cutout, and press the release switch while pulling outward on the handle to open the liftgate.
To open the power liftgate, press and release the "Liftgate Open" button on the keyless entry remote two times within five seconds. Alternatively, you can press and release the "Liftgate Open" button -- the right, rear button -- on the overhead console to open the power liftgate.