Power Lift Gate will not raise or lower.

These are complex systems, one little voltage problem and they are messed up, so if the battery was replaced without using the saver tool that plugged into the OBD 2 port then you have to go to the dealer and have it reprogrammed back into the onboard system.

Your owners manual coves this over about seven pages. Could be the liftgate latch fuse or the latch or latch motor, especially in a van that's over ten years old. If there was an electrical interruption, it might just need to be reset. If you don't know cars, have a mechanic address this, it's not likely due to damage, like failure of a part.