There is not enough room behind the device to just unplug and plug in the new lamp.  I tried to remove the assembly by taking out the two screws at the top that hold it in place.  This loosened the assembly, but would not allow me to remove it.How do i change a headlight on my  2005 Chrysler Pacifica?
FIRST, make sure you put a small hand towel under the headlight bezel. Push it in under the headlight assembly and between the front facia. This will help keep you from scractching your chrome Bezelette (bumper insert). Kind of tricky the first time but after you do it once, it is a piece of cake. The hard part is popping it out of the snaps. 
Here is the factory service manual instructions: 
 
REMOVAL 
Open hood, disconnect and isolate the battery 
negative cable. 
Remove the two headlamp unit retaining 
screws. (two screws on top) 
Gently pull headlamp unit forward, unsnapping 
it from the lower retaining clip. Be 
careful not to damage lower retaining clip upon 
removal. It also helps if you wiggle it side to side and pull at the same time.
Disconnect the headlamp unit electrical connector. 
Connect the headlamp unit electrical connect. 
Gently place the headlamp unit into the body 
opening. Make sure the lower retaining clip is placed 
on the retaining bar on the bottom of the headlamp 
unit. Be careful not to damage lower retaining 
clip upon installation. 
Install the two headlamp unit retaining screws 
Reinstall the battery negative cable. 
Verify vehicle and system operation.How do i change a headlight on my  2005 Chrysler Pacifica?
Try lookin at the manuel that came with the car or take it into the dealer ship
