With the lkey itself but it only works on driver side
To open a Chrysler Pacifica rear hatch without power, locate the manual release mechanism, typically found near the latch inside the hatch area. You may need to remove a panel or cover to access it. Alternatively, if the vehicle’s battery is dead, try using a physical key to unlock the doors, and then manually open the hatch from the inside. Always consult the owner's manual for specific instructions related to your model.
To reprogram a 2005 Chrysler Pacifica key fob, first, insert the key into the ignition and turn it to the "On" position without starting the engine. Press and hold the "Unlock" button on the key fob while turning the ignition back to the "Off" position, then back to "On" again. Release the "Unlock" button and press the "Lock" button on the fob within 5 seconds. Repeat this process for any additional fobs you wish to program, as the system can program up to four fobs.
try unlocking it from the driver side...the chip in the key should keep the alarm from sounding...it works for my sportage...
Unlock the doors or trunk with the key.
To disable the alarm in a Chrysler 300C, you can simply unlock the driver's side door with the key or use the key fob to unlock the vehicle. If the alarm is sounding, inserting the key in the ignition and turning it to the "On" position may also silence it. Additionally, you can press the panic button on the key fob to stop the alarm. If the issue persists, consult the owner's manual for further guidance.
Contact a Chrysler dealer
The emergency rear hatch release for a 2005 Chrysler Pacifica is typically located inside the vehicle, near the rear hatch area. You may find it on the ceiling near the rear hatch or on the side panel near the rear seats. It is usually a pull lever or a button that can be used to manually unlock and open the hatch in case of a power failure. Always refer to the owner’s manual for specific details related to your vehicle.
I'm assuming your horns sounding because the alarm was activated that's the case then put your key in the drivers door lock and unlock and lock again ,see if that works if not disconnect the battery.
NOT
You can still unlock the door with the key.
You unlock the door with the key or with the remote.