The liftgate on my 2004 feestar will not unlock with the remote. It did this once before and then started working again. I cannot open it since there is no way to unlock it manually that I can find.

SOURCE: 2003 Saturn Vue rear liftgate won't open

The easy part is you just need the latch for the liftgate. The hard part is getting to it and opening the liftgate to replace the latch. You should be able to pull the liftgate trim off most of the way with the gate closed and try to manually actuate the latch to open the gate. You may have to go so far as breaking the latch from the inside to open the gate and then replace your latch.

SOURCE: 2002 Chrysle Town & Country Power liftgate won't open.

Replace the lock on the rear door. If a used lock is used it has to have the powered door. I am a car dealer and have replaced about 8-9 of them. I sell a lot of Town & Country vans. The 1st one I paid a Chrysler dealer to fix. About $200. After that I fix myself. About $70- $125 from a Chrysler dealer new with discount. The lock is not sending the correct code to the computer and the door is confused on what to do. Only 3 torx bolts to remove and the door panel 2 screws in handle then snap off.
On one I had that did not fix the problem and it was a relay sensor about $40. on the working arm / motor of the door and not the lock. Look at car-part.com for used parts. Thanks, Roy

SOURCE: power liftgate doesn't work

The power liftgate motor is located on the driver side panel directly behind the lift arm. First you will have to take the safety belt bolt out. After you get the plastic piece free from the body you will have to take the bolt out of the arm that connects to the hatch. Make sure you have a big enough torx bit for the bolt that holds the arm to the gate. This will allow you to slide the plastic piece off and out of your way. If you are having trouble getting the plastic piece to come off from around the liftgate arm, try putting the door down, that helped me. The rest should be easy. Hope this info helped you out. 

SOURCE: I actually have a 2004 Freestar the liftgate is

faulty lock motor (solynoid) remove door trim to gain access when removed try unlocking with key manualy

SOURCE: liftgate will not unlock even when unlock button

The latch is seized. You will have to manually unlock it by removing the panel on the inside of the liftgae.